1) Succession is best described as A. a process whereby different organisms
systematically colonize a barren habitat until a stable community is formed. B.
a process whereby plants occupy a barren habitat until a suitable habitat is
formed. C. a process whereby animals occupy a barren habitat until a suitable
habitat is formed. D. the subsequent taking over of the land through emigration
or dispersal of seeds. E. the replacement of weaker plants and animals by the
stronger ones.

Topics of the question: Ecology, Ecological Succession

Correct option: A

Explanation: Ecological succession is the process of change in the species
structure of an ecological community over time. The process involves pioneer
organisms colonizing a barren or disturbed area and gradually being replaced by
more complex and stable communities until a climax community is reached. Option
A accurately describes this process.

2) Predators are beneficial in pest control because they A. are natural enemies
of small mammals. B. devour farm animals. C. feed on pest of crops. D. prey on
game animals. E. compete for food with the pests.

Topics of the question: Ecology, Pest Control, Food Chains

Correct option: C

Explanation: In the context of pest control, predators are beneficial because
they naturally feed on organisms considered “pests,” such as insects or small
rodents that damage crops. This reduces pest populations without the need for
chemical interventions.

3) Which of the following organisms are transmitted by houseflies? I. Plasmodium
II. Vibrio cholerae III. Gonococcus sp. IV. Poliomyelitis virus V. Syphilis
bacteria A. I and II only B. II and V only C. III and IV only D. II and IV only
E. III and V only

Topics of the question: Disease Transmission, Vectors, Microorganisms

Correct option: D

Explanation: Houseflies are known vectors for various pathogens.

– Vibrio cholerae (causes cholera) can be transmitted by flies that land on
contaminated faeces and then on food.
– Poliomyelitis virus (causes polio) can also be transmitted mechanically by
flies.
– Plasmodium (malaria) is transmitted by mosquitoes.
– Gonococcus sp. (gonorrhea) and Syphilis bacteria are primarily sexually
transmitted. Therefore, II and IV are the correct options.

4) The practice of warming soup regularly as it concerns food preservation is
essentially to A. retain the taste. B. help to break down the cellulose. C.
remove the excess water. D. kill the bacteria in it. E. raise the temperature.

Topics of the question: Food Preservation, Microbiology

Correct option: D

Explanation: Warming soup regularly, especially to a high temperature, is a
common food preservation technique. The heat kills or significantly reduces the
number of bacteria and other microorganisms that can cause spoilage or foodborne
illness, thereby extending the soup’s shelf life.

5) Agglutination occurs in blood transfusion when the A. donor and the recipient
belong to the same blood group. B. same antibodies from donor and recipient fuse
together. C. donor and the recipient belong to different races. D. recipient is
not a universal recipient. E. antigen and antibody in the donor and the
recipient react.

Topics of the question: Human Biology, Blood Groups, Transfusion

Correct option: E

Explanation: Agglutination (clumping of red blood cells) in a blood transfusion
is a severe reaction that occurs when there is an incompatibility between the
donor’s antigens and the recipient’s antibodies. Specifically, if the
recipient’s antibodies recognize and bind to antigens on the donor’s red blood
cells, they will cause the cells to clump together.

6) Which of the following is not a way of conserving natural resources? A.
Controlling farming practices. B. Establishing forest reserves C. Establishing
of parks and gardens. D. Encouraging poaching in game reserves. E. Protecting
the endangered species.

Topics of the question: Environmental Conservation, Natural Resources

Correct option: D

Explanation: Conservation aims to protect and manage natural resources.

– A, B, C, and E are all valid methods of conservation.
– Encouraging poaching in game reserves directly contradicts conservation
efforts, as poaching involves illegally hunting animals, leading to
depletion of wildlife populations.

7) Which of the following limiting resources is competed for by organisms in the
desert? A. Light B. Temperature C. Oxygen D. Water E. Carbon dioxide

Topics of the question: Ecology, Limiting Factors, Desert Ecosystems

Correct option: D

Explanation: Deserts are characterized by extreme aridity. Water is the most
critical and often scarce resource in desert environments, making it the primary
limiting factor for most organisms, leading to intense competition for its
availability.

8) The adaptations for water conservation in organisms include the following
except A. scales in fishes. B. scales on leaves. C. thick leaves. D. spine in
plants. E. succulent stems.

Topics of the question: Adaptations, Water Conservation, Plants, Animals

Correct option: A

Explanation:

– Scales on leaves (e.g., some desert plants) reduce water loss.
– Thick leaves (e.g., succulents) store water.
– Spines in plants (modified leaves) reduce surface area for transpiration and
protect water stores.
– Succulent stems (e.g., cacti) store large amounts of water.
– Scales in fishes are primarily for protection, streamlining, and
osmoregulation in an aquatic environment, not for conserving water in the
sense of preventing evaporation from the body surface.

9) Which of the following structures is a protective adaptive feature of the
Agama lizard to terrestrial habitat? A. Claws B. Gular fold C. Scaly skin D.
Nuchal crest E. Tail…

Topics of the question: Animal Adaptations, Terrestrial Animals, Reptiles

Correct option: C

Explanation:

– Scaly skin is a key adaptation for terrestrial reptiles like the Agama
lizard. It provides protection against abrasion, helps prevent water loss
through evaporation (a major challenge in terrestrial environments), and
offers a barrier against pathogens.
– Claws are for gripping/climbing.
– Gular fold is often involved in display or thermoregulation.
– Nuchal crest is for display.
– The tail has various functions (balance, fat storage, defense).

10) Which of the following statements best explains the term aestivation? A. A
device for survival during the period of extreme food and water shortage B. A
method of survival adopted by plants during the dry season C. Movement of
animals over long distances D. A method of survival adopted by animals under
favourable condition E. A divice for rapid multiplication during abundance of
food.

Topics of the question: Animal Adaptations, Survival Strategies

Correct option: A

Explanation: Aestivation is a state of animal dormancy, similar to hibernation,
characterized by inactivity and a lowered metabolic rate, that occurs in
response to high temperatures and arid conditions. It allows animals to survive
periods of extreme heat, drought, or food scarcity.

11) The phenomenon whereby some organisms with certain features get established
in an environment is known as A. partial selection. B. artificial selection C.
natural selection D. mutation E. colonization.

Topics of the question: Evolution, Adaptation, Ecology

Correct option: C

Explanation: This describes natural selection, a fundamental mechanism of
evolution. Organisms with traits that are better suited to their environment are
more likely to survive, reproduce, and pass on those advantageous traits to
their offspring, leading to the establishment of these features in the
population over time.

12) Who formulated the theory of natural selection in evolution? A. Louis
Pasteur B. Robert Hooke C. Jean Lamarck D. Mathias Schleiden E. Charles Darwin.

Topics of the question: History of Biology, Evolution

Correct option: E

Explanation: Charles Darwin is credited with formulating the theory of evolution
by natural selection. Alfred Russel Wallace independently conceived a similar
theory around the same time.

13) The wing of a bat and that of a bird, the flippers of a whale and the fins
of a fish are examples of A. adaptive radiation. B. vestigial structures. C.
continuous variation. D. convergent evolution. E. divergent evolution.

Topics of the question: Evolution, Analogous Structures, Convergent Evolution

Correct option: D

Explanation: The structures listed (bat wing, bird wing, whale flipper, fish
fin) serve similar functions (flight or swimming) but have evolved independently
in different lineages. They do not share a recent common ancestor that possessed
the structure in that form. This is an example of convergent evolution, where
different species evolve similar traits due to similar selective pressures.

14) In an individual who is heterozygous for a particular character, the
hereditary factor that is always expressed is described as a A. allele. B.
sickle-cell gene. C. dominant gene. D. chromosome. E. sex-linked character.

Topics of the question: Genetics, Mendelian Inheritance

Correct option: C

Explanation: In a heterozygous individual (having two different alleles for a
trait), the allele that is expressed and masks the effect of the other allele is
called the dominant gene (or dominant allele).

15) Which of the following statements best explains the meaning of homologous
chromosomes? A. product of division of chromosomes. B. Two identical chromosomes
from each parent. C. chromosomes arranged on spindle fibre during cell division
D. Chromosomes arranged on the equatorial plate of the cell E. Daughter
chromatids in the first meiotic division

Topics of the question: Genetics, Cell Division, Chromosomes

Correct option: B

Explanation: Homologous chromosomes are a pair of chromosomes (one inherited
from each parent) that are similar in length, gene position, and centromere
location. They carry genes for the same traits at corresponding loci, although
the alleles for those genes may be different.

16) Which of the following reagents is used for the test for starch? A. Millon’s
reagent B. Fehling’s solution C. Sudan III D. Iodine solution E. Benedict’s
solution

Topics of the question: Biochemistry, Food Tests

Correct option: D

Explanation: Iodine solution (Lugol’s iodine) is used to test for starch. Starch
reacts with iodine to produce a characteristic blue-black or purple color.

17) Which of the following is an autotrophic mode of nutrition? A.
Chemosynthesis B. Saprophytism C. Parasitism D. Symbiosis E. Commensalism

Topics of the question: Nutrition, Autotrophs

Correct option: A

Explanation: Autotrophic nutrition involves organisms producing their own food.
While photosynthesis is the most common form, chemosynthesis is another
autotrophic process where organisms (chemoautotrophs) use energy from the
oxidation of inorganic chemical compounds to synthesize organic molecules.
Saprophytism and parasitism are heterotrophic, while symbiosis and commensalism
describe relationships, not necessarily nutrition type.

18) Which of the following is not a way of reducing air pollution? A. Siting
factories and power stations away from residential areas B. Building tall
factory chimneys C. Passing waste gases through filters and absorbers D. Using
lead-free petrol in cars E. Recycling tins, cans and bottles.

Topics of the question: Environmental Science, Pollution Control

Correct option: E

Explanation:

– A, C, and D are all direct methods to reduce air pollution by either
dispersing pollutants, treating emissions, or using cleaner fuels.
– Building tall factory chimneys helps disperse pollutants higher into the
atmosphere, which can reduce local ground-level concentration but doesn’t
reduce the total amount of pollutants released. It’s a dispersion strategy
rather than a reduction strategy.
– Recycling tins, cans and bottles is a method of waste management and
resource conservation, which indirectly reduces the energy needed for new
production (and thus associated pollution), but it’s not a direct way of
reducing air pollution from emissions.

19) Which of the following factors is not associated with aquatic habitat? A.
Temperature B. Light intensity C. Turbidity D. Wave action E. Humidity

Topics of the question: Ecology, Aquatic Ecosystems, Environmental Factors

Correct option: E

Explanation:

– Temperature, light intensity, turbidity (clarity of water), and wave action
are all significant physical factors that characterize and influence aquatic
habitats.
– Humidity refers to the amount of moisture in the air and is a characteristic
of terrestrial or atmospheric environments, not directly an aquatic factor.

20) Which of the following types of soil has the highest water-retaining
capacity? A. Clay B. Laterite C. Loam D. Gravel E. Sand

Topics of the question: Soil Science, Water Retention

Correct option: A

Explanation: Clay soil has very fine particles and a large surface area, which
allows it to hold a significant amount of water. Sand has large particles and
poor water retention. Loam is a mixture and has good water retention but
generally less than pure clay.

21) Changes in energy flow between organisms in a habitat can be represented by
a A. Pyramid of biomass. B. Pyramid of numbers. C. Pyramid of energy D. food
chain. E. food web.

Topics of the question: Ecology, Energy Flow, Trophic Levels

Correct option: C

Explanation: A pyramid of energy (or ecological pyramid) is the most accurate
representation of energy flow between trophic levels in an ecosystem. It always
shows a decrease in energy at successive trophic levels because energy is lost
as heat at each transfer. Pyramids of biomass and numbers can sometimes be
inverted, but a pyramid of energy is always upright.

22) Which of the following processes is not involved in the carbon cycle? A.
Burning B. Decay C. Transpiration D. Respiration E. Photosynthesis.

Topics of the question: Biogeochemical Cycles, Carbon Cycle

Correct option: C

Explanation:

– Burning (combustion of fossil fuels/biomass) releases CO2.
– Decay (decomposition) releases CO2.
– Respiration (by living organisms) releases CO2.
– Photosynthesis (by plants and other autotrophs) absorbs CO2.
– Transpiration is the process of water movement through a plant and its
evaporation from aerial parts, such as leaves. It is part of the water
cycle, not the carbon cycle.

23) Which of the following processes are involved in a water cycle? A.
Evaporation, condensation and precipitation B. Evaporation, percolation and
transpiration C. Evaporation and precipitation D. Evaporation and transpiration
E. precipitation and condensation

Topics of the question: Biogeochemical Cycles, Water Cycle

Correct option: A

Explanation: The fundamental processes of the water cycle involve water changing
states and locations.

– Evaporation: Water turning into vapor and rising into the atmosphere.
– Condensation: Water vapor cooling and forming clouds.
– Precipitation: Water falling back to Earth as rain, snow, etc.
– Percolation (water filtering through soil) and transpiration (water release
from plants) are also parts of the water cycle, but option A represents the
core atmospheric processes.

24) Water in the human body is derived from the following sources except through
A. drinking water. B. food substance. C. cytoplasm of worn-out cells. D.
respiratory activity. E. absorption by the skin.

Topics of the question: Human Biology, Water Balance

Correct option: E

Explanation: The human body obtains water primarily from:

– Drinking water and other beverages.
– Food substances (many foods have high water content).
– Metabolic water produced during cellular respiration (sometimes referred to
indirectly in “respiratory activity” or the breakdown of molecules).
– Cytoplasm of worn-out cells also refers to the water released during the
breakdown of cells and their components.
– Absorption by the skin is not a significant source of water for the human
body; the skin acts more as a barrier to water loss.

25) The conservation of natural resources can be achieved by the following
except A. creation of national parks B. formation of conservation societies and
agencies. C. establishment of game reserves. D. deregulated harvesting. E.
making laws on conservation.

Topics of the question: Environmental Conservation, Natural Resources

Correct option: D

Explanation:

– A, B, C, and E are all established methods and strategies for conserving
natural resources.
– Deregulated harvesting means removing regulations or controls on how
resources are harvested. This would lead to uncontrolled exploitation and
depletion of resources, directly opposing conservation goals.

26) Water rises most rapidly in A. sandy soil. B. clayey soil. C. sandy-loam
soil. D. loamy soil. E. humus soil.

Topics of the question: Soil Science, Capillary Action

Correct option: A

Explanation: Water rises most rapidly (due to capillary action) in soils with
larger pore spaces that are well-connected. Sandy soil typically has larger,
more uniform pore spaces compared to clay or loam, allowing water to move
upwards more quickly, although its total water-holding capacity is lower.

27) Thrombocytes are blood cells responsible for initiating A. phagocytosis of
bacteria. B. synthesis of ribosomes. C. clotting of the blood. D. immunity to
certain infectious diseases. E. removal of carbon dioxide from tissues.

Topics of the question: Human Biology, Blood Components

Correct option: C

Explanation: Thrombocytes, also known as platelets, are essential for hemostasis
(the process of stopping bleeding). They aggregate at the site of injury and
release factors that initiate the complex cascade of reactions leading to blood
clotting.

28) When gametes from pure breeding parents with contrasting features such as
tallness and shortness are involved in monohybrid cross, the offspring in the
first filial generation are usually A. pure breed B. heterozygous dominant. C.
homozygous recessive. D. mutants. E. co-dominant.

Topics of the question: Genetics, Mendelian Inheritance, Monohybrid Cross

Correct option: B

Explanation: In a monohybrid cross between two pure-breeding parents with
contrasting traits (e.g., TT x tt), all offspring in the first filial (F1)
generation will inherit one dominant allele and one recessive allele (Tt).
Therefore, they will be heterozygous and express the dominant phenotype.

29) A pair of genes which controls a trait is described as a A. dominant B.
recessive C. allele D. variant E. hybrid.

Topics of the question: Genetics, Terminology

Correct option: C

Explanation: An allele is one of two or more alternative forms of a gene that
arise by mutation and are found at the same place on a chromosome. A pair of
alleles (one from each parent) controls a particular trait.

30) The genetic make-up of an organism is described as its A. phenotype B.
genotype. C. character. D. chromosome. E. allele.

Topics of the question: Genetics, Terminology

Correct option: B

Explanation: The genotype refers to the complete set of genes (genetic
constitution) of an organism. The phenotype is the observable physical or
biochemical characteristics expressed by that genotype.

31) The precondition for transfusion of blood to an accident victim is A.
seeking the consent of his parents. B. ascertaining the religious belief of the
victim. C. cross-matching the blood group of the donor with that of the accident
victim. D. curing the donor of any disease traced in his blood. E. rewarding the
donor with food and money.

Topics of the question: Human Biology, Blood Transfusion

Correct option: C

Explanation: The most critical precondition for a safe blood transfusion is
cross-matching the blood group of the donor with that of the recipient. This
ensures compatibility and prevents a potentially fatal agglutination reaction.
In emergencies, O-negative blood (universal donor) may be used if cross-matching
is not immediately possible.

32) Adaptive radiation as illustrated in the variety of forms in insects can be
regarded as a A. behavioural modification. B. a case of rapid population growth.
C. a physiological process. D. an evidence of evolution. E. a population control
mechanism

Topics of the question: Evolution, Adaptive Radiation

Correct option: D

Explanation: Adaptive radiation is the diversification of a group of organisms
into forms filling different ecological niches. The vast variety of forms and
adaptations seen in insects (e.g., different mouthparts, wing types, life
cycles) is a prime example and strong evidence of evolution.

33) Which of the following statements about the modifications of pentadactyl
fore-limb is not correct? A. Wings are modified for flying in birds. B. Flippers
are modified for grasping in sharks. C. Legs are modified for walking and
running in antelopes. D. Arms are adapted for grasping and holding in human
beings. E. Flippers are modified for swimming in whales.

Topics of the question: Evolution, Comparative Anatomy, Homologous Structures

Correct option: B

Explanation: The pentadactyl forelimb is a homologous structure found in many
vertebrates.

– A, C, D, and E correctly describe modifications of the pentadactyl limb for
various functions.
– Flippers in sharks are not modified pentadactyl forelimbs. Sharks are fish
with cartilaginous skeletons and their fins (including pectoral fins which
are analogous to forelimbs) have a fundamentally different skeletal
structure from the bony pentadactyl limb of tetrapods (mammals, birds,
reptiles, amphibians). Whale flippers are modified pentadactyl limbs.

34) The process by which plants and animals are modified in structure,
physiology and behaviour in order to survive is known as A. evolution B.
adaptation. C. succession. D. aggregation E. hibernation.

Topics of the question: Biology, Adaptations, Survival

Correct option: B

Explanation: Adaptation is the evolutionary process whereby an organism becomes
better suited to its habitat. It refers to the features (structural,
physiological, or behavioral) that enable an organism to survive and reproduce
in its environment. Evolution is the broader process that leads to adaptations.

35) What is the significance of the bee dance to other bees? A. Warning signal
B. Presence of food C. Mating signal by the male D. Scaring the enemies away E.
Time for nuptial flight.

Topics of the question: Animal Behavior, Communication, Insects

Correct option: B

Explanation: The “waggle dance” performed by honeybees is a sophisticated form
of communication. It signals to other worker bees the direction and distance to
a food source (nectar or pollen).

36) Which of the following statement is not associated with the theory of
natural selection? A. There is a struggle for existence B. There is competition
among the offsprings. C. The weaker offsprings are eliminated. D. Food and other
needs are abundant E. Nature selects those that survive to reproduce their kind.

Topics of the question: Evolution, Natural Selection

Correct option: D

Explanation: The theory of natural selection is based on several key principles:

– Overproduction and struggle for existence (A)
– Competition for limited resources (B)
– Variation among individuals, with fitter individuals surviving and
reproducing (leading to the elimination of less fit/weaker offspring) (C, E)
– Food and other needs are abundant (D) contradicts the principle of limited
resources and the struggle for existence, which are driving forces of
natural selection. If resources were abundant, there would be less
competition and selective pressure.

37) The stems of young herbaceous plants are kept upright mainly by A. osmotic
pressure. B. turgor pressure. C. transpiration pull. D. suction pressure. E.
root pressure.

Topics of the question: Plant Biology, Water Relations

Correct option: B

Explanation: In young herbaceous (non-woody) plants, the cells are supported by
turgor pressure. When plant cells absorb water, their vacuoles swell and push
the cell membrane against the cell wall, creating internal pressure that makes
the cells firm and helps the stem remain upright. Loss of turgor pressure causes
wilting.

38) Different tissues in plants contribute to the support of the parts as a
result of the following characteristics except A. malleability B. rigidity C.
flexibility D. resilience E. hardness.

Topics of the question: Plant Anatomy, Plant Support

Correct option: A

Explanation: Plant tissues like xylem (lignified walls), collenchyma (thickened
cell walls), and sclerenchyma (sclereids and fibers) provide support through
properties such as:

– Rigidity (stiffness)
– Flexibility (ability to bend without breaking)
– Resilience (ability to return to original shape after deformation)
– Hardness (resistance to deformation).
– Malleability is the ability of a material to be hammered or pressed into
shape without breaking. This is not a characteristic that contributes to
structural support in plants; it’s more associated with metals.

39) Water vapour is lost in plants during transpiration through A. stomata and
lenticels. B. xylem and stomata C. sclerenchyma and stomata D. parenchyma and
lenticels E. guard cells and lenticels.

Topics of the question: Plant Physiology, Transpiration

Correct option: A

Explanation: The primary sites for water vapor loss (transpiration) in plants
are:

– Stomata: Small pores on the leaf surface, controlled by guard cells.
– Lenticels: Pores on the bark of woody stems and roots. While a small amount
can occur directly through the cuticle, these two structures are the main
regulated openings.

40) Gaseous exchange takes place in the adult toad through the A. buccal cavity,
bladder and lungs. B. buccal cavity, skin and lungs. C. tympanic membrane, lung
and gills. D. buccal cavity, skin and spiracle. E. gills, skin and buccal
cavity.

Topics of the question: Animal Physiology, Respiration, Amphibians

Correct option: B

Explanation: Adult toads (amphibians) use multiple surfaces for gaseous
exchange:

– Buccal cavity (mouth lining): Through rhythmic movements, air is drawn in
and oxygen exchanged.
– Skin: Moist, permeable skin allows for cutaneous respiration.
– Lungs: Simple lungs are present for pulmonary respiration. Gills are
typically present in larval stages (tadpoles), and spiracles are
characteristic of insects.

41) Breathing movement in mammals is accompanied by regular movements of the
diaphragm and the A. intercostal muscles. B. vertebral column. C. clavicle. D.
pleural cavity. E. floating ribs.

Topics of the question: Human Biology, Respiratory System

Correct option: A

Explanation: In mammals, breathing (ventilation) involves the coordinated action
of the diaphragm (a dome-shaped muscle below the lungs) and the intercostal
muscles (muscles between the ribs). Contraction of these muscles changes the
volume of the thoracic cavity, leading to inhalation and exhalation.

42) Which of the following are components of glomerular filtrate? A. All the
components of blood except mineral salts. B. Water and salt only. C. All the
components of blood except plasma protein and cells. D. Plasma proteins, red and
white blood cells E. Blood cells, amino acid, salts and nitrogenous wastes.

Topics of the question: Human Biology, Kidney, Excretion

Correct option: C

Explanation: Glomerular filtration is the first step in urine formation in the
kidney. Blood is filtered from the glomerulus into Bowman’s capsule. The
filtrate is essentially plasma minus large molecules like plasma proteins and
blood cells (red blood cells, white blood cells, platelets), which are too large
to pass through the filtration barrier. Smaller molecules like water, salts,
glucose, amino acids, and nitrogenous wastes pass through.

43) The mechanism by which useful materials in the glomerular filtrate are taken
back into the blood is known as A. filtration. B. reabsorption. C. haemolysis.
D. osmosis. E. dialysis.

Topics of the question: Human Biology, Kidney, Excretion

Correct option: B

Explanation: After filtration, the glomerular filtrate contains both waste
products and useful substances. The process of selectively taking back essential
substances (like water, glucose, amino acids, and some salts) from the renal
tubules back into the blood is called reabsorption.

44) Which of the following takes place during the process of detoxification in
the liver? A. Poisonous substances in the body are converted into harmless
substances. B. Fats and oils are broken into finer particles through
emulsification. C. Excess glucose in the blood are converted into glycogen and
stored. D. Worn-out red blood cells are broken down. E. Enough heat is generated
to sustain the activities of the liver.

Topics of the question: Human Biology, Liver, Metabolism

Correct option: A

Explanation: One of the liver’s major functions is detoxification. This involves
converting harmful or poisonous substances (e.g., drugs, alcohol, metabolic
byproducts) into less toxic or harmless compounds that can be excreted from the
body.

45) The cup-shaped part of the Bowman’s capsule contains the A. nephridium. B.
glomerulus. C. loop of Henle D. nephron. E. convoluted tubule.

Topics of the question: Human Biology, Kidney, Excretion

Correct option: B

Explanation: Bowman’s capsule is the cup-shaped sac at the beginning of the
tubular component of a nephron. It encloses the glomerulus, which is a capillary
tuft where blood filtration takes place. Together, the Bowman’s capsule and
glomerulus form the renal corpuscle.

46) The increase in width of blood vessels in the mammalian skin at high
temperatures is known as A. vasodilation. B. sweating. C. vasoconstriction. D.
shivering. E. evaporation.

Topics of the question: Human Biology, Thermoregulation

Correct option: A

Explanation: When body temperature rises, the blood vessels in the skin dilate
(vasodilation). This increases blood flow near the surface of the skin, allowing
more heat to be dissipated from the body to the environment, thus helping to
cool the body.

47) The condition known as cretinism is caused by the deficiency of A.
adrenalin. B. vitamin A. C. insulin. D. thyroxin. E. vitamin C.

Topics of the question: Human Biology, Endocrine System, Deficiency Diseases

Correct option: D

Explanation: Cretinism (now often called congenital hypothyroidism) is a
condition of severely stunted physical and mental growth due to untreated
congenital deficiency of thyroid hormones (thyroxin).

48) Which of the following parts of the mammalian brain is involved in taking
the decision to run rather than walk? A. Cerebellum. B. Medulla oblongata C.
Cranial nerves D. Mid brain E. Cerebrum.

Topics of the question: Human Biology, Nervous System, Brain Function

Correct option: E

Explanation: The cerebrum (specifically the frontal lobes) is responsible for
higher-level cognitive functions, including conscious thought, decision-making,
planning, and voluntary movements. The decision to run or walk is a conscious,
voluntary choice originating in the cerebrum.

49) The brain and spinal cord make up the A. peripheral nervous system. B.
autonomic nervous system. C. central nervous system. D. somatic nervous system
E. sympathetic nervous system.

Topics of the question: Human Biology, Nervous System

Correct option: C

Explanation: The nervous system is divided into two main parts:

– Central Nervous System (CNS): Consists of the brain and spinal cord.
– Peripheral Nervous System (PNS): Consists of all nerves outside the CNS.

50) Which of the following is not true about auxins? They A. are manufactured by
plants. B. are used in the site of production. C. are normally present in minute
quantities in the cells of plants. D. regulate growth rate of plants. E.
regulate direction of growth in plants.

Topics of the question: Plant Hormones, Auxins

Correct option: B

Explanation:

– A, C, D, and E are all true statements about auxins. Auxins are plant
hormones produced primarily in shoot tips and young leaves.
– Auxins are not “used” in the site of production in the sense of being
consumed there to perform their main action. Instead, they are produced
there and then transported to other parts of the plant where they exert
their effects on growth and development (e.g., cell elongation, apical
dominance).

51) Which of the following stimuli are not perceived through the skin of
mammals? A. Light B. Pressure C. Pain D. Heat E. Cold

Topics of the question: Human Biology, Senses, Skin

Correct option: A

Explanation: The skin contains various sensory receptors that allow mammals to
perceive:

– Pressure (touch)
– Pain
– Heat
– Cold
– Light is primarily perceived by the eyes (photoreceptors in the retina), not
by receptors in the skin.

52) Which of the following parts of the tongue does not correspond to the taste
indicated against it? A. Tip-sweet B. Centre-salt C. Back-sour D. Side-sour E.
Back-bitter

Topics of the question: Human Biology, Senses, Taste Buds

Correct option: B

Explanation: The idea of distinct “taste zones” on the tongue (e.g., “sweet
tip,” “bitter back”) is a common misconception, often referred to as the “tongue
map.” While some areas might be slightly more sensitive to certain tastes, all
taste buds can detect all five basic tastes (sweet, sour, salty, bitter, umami).
Therefore, the statement that the “Centre” is exclusively or primarily for
“salt” is incorrect in the context of modern understanding. However, if forced
to choose based on the traditional (and outdated) “tongue map,” the center was
often depicted as a “neutral” zone, not specifically salty.