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Question-1 Which of the following lipids is a major component of cell membranes?
a) Triglycerides
b) Phospholipids
c) Steroids
d) Waxes
Answer: b) Phospholipids
Explanation:
Phospholipids have a hydrophilic head and a hydrophobic tail, making them ideal for forming the lipid bilayer of cell membranes.
Question-2 Which fatty acid is essential and must be obtained from the diet?
a) Stearic acid
b) Oleic acid
c) Linoleic acid
d) Palmitic acid
Answer: c) Linoleic acid
Explanation:
Linoleic acid is an essential polyunsaturated fatty acid that humans cannot synthesize.
Question-3 Which of the following is NOT a function of proteins?
a) Structural support
b) Enzyme activity
c) Genetic information storage
d) Transport molecules
Answer: c) Genetic information storage
Explanation:
Genetic information is stored in nucleic acids (DNA and RNA), not proteins.
Question-4 The bond that links amino acids in proteins is called:
a) Hydrogen bond
b) Peptide bond
c) Glycosidic bond
d) Ester bond
Answer: b) Peptide bond
Explanation:
A peptide bond forms between the carboxyl (-COOH) group of one amino acid and the amine (-NH₂) group of another.
Question-5 Which nitrogenous base is found in RNA but not in DNA?
a) Adenine
b) Thymine
c) Uracil
d) Guanine
Answer: c) Uracil
Explanation:
RNA contains uracil (U) instead of thymine (T), which is found in DNA.
Question-6 The functional unit of the kidney is called:
A) Nephron
B) Neuron
C) Glomerulus
D) Alveolus
Answer: A) Nephron
Explanation:
The nephron is the structural and functional unit of the kidney responsible for filtration and urine formation.
Question-7 Which part of the nephron is responsible for ultrafiltration?
A) Loop of Henle
B) Collecting duct
C) Glomerulus
D) Ureter
Answer: C) Glomerulus
Explanation:
The glomerulus, a network of capillaries, filters blood under high pressure, allowing the passage of small molecules into the nephron.
Question-8 Which hormone regulates water reabsorption in the kidneys?
A) Insulin
B) ADH (Antidiuretic Hormone)
C) Oxytocin
D) Aldosterone
Answer: B) ADH (Antidiuretic Hormone)
Explanation:
ADH increases water reabsorption in the kidney’s collecting ducts, reducing urine volume and conserving water.
Question-9 Which part of the nephron is involved in countercurrent mechanism?
A) Proximal convoluted tubule
B) Distal convoluted tubule
C) Loop of Henle
D) Bowman’s capsule
Answer: C) Loop of Henle
Explanation:
The Loop of Henle helps maintain an osmotic gradient, allowing efficient water and ion reabsorption through countercurrent exchange.
Question-10 What is the yellow pigment in urine called?
A) Bilirubin
B) Urochrome
C) Hemoglobin
D) Melanin
Answer: B) Urochrome
Explanation:
Urochrome, a pigment formed from hemoglobin breakdown, gives urine its characteristic yellow color.
Question-11 Which is the longest part of the human digestive system?
A) Stomach
B) Small intestine
C) Esophagus
D) Large intestine
Answer: B) Small intestine
Explanation:
The small intestine is approximately 6 meters long and plays a major role in digestion and absorption.
Question-12 What is the function of bile in digestion?
A) Digests proteins
B) Emulsifies fats
C) Breaks down starch
D) Produces insulin
Answer: B) Emulsifies fats
Explanation:
Bile, secreted by the liver, breaks down large fat molecules into smaller droplets for easier digestion.
Question-13 The enzyme pepsin is responsible for digesting:
A) Fats
B) Proteins
C) Carbohydrates
D) Nucleic acids
Answer: B) Proteins
Explanation:
Pepsin is a protease enzyme secreted by the stomach that breaks down proteins into smaller peptides.
Question-14 Which of the following is a function of the large intestine?
A) Absorption of nutrients
B) Digestion of fats
C) Water and electrolyte absorption
D) Secretion of bile
Answer: C) Water and electrolyte absorption
Explanation:
The large intestine absorbs water and minerals and compacts undigested food into feces.
Question-15 What is the dental formula of an adult human?
A) 2,1,2,3 / 2,1,2,3
B) 2,2,1,3 / 2,2,1,3
C) 1,2,3,2 / 1,2,3,2
D) 2,1,3,2 / 2,1,3,2
Answer: A) 2,1,2,3 / 2,1,2,3
Explanation:
Humans have heterodont dentition, with 2 incisors, 1 canine, 2 premolars, and 3 molars in each half of the jaw.
Question-16 What is the main product of anaerobic respiration in yeast?
A) Lactic acid
B) Ethanol
C) Acetyl CoA
D) Succinic acid
Answer: B) Ethanol
Explanation:
Yeast undergoes alcoholic fermentation, producing ethanol and CO₂.
Question-17 Which process generates the most ATP per glucose molecule?
A) Glycolysis
B) Krebs cycle
C) Electron Transport Chain (ETC)
D) Fermentation
Answer: C) Electron Transport Chain (ETC)
Explanation:
The ETC generates about 34 ATP molecules per glucose.
Question-18 What is the end product of glycolysis?
A) Acetyl CoA
B) Pyruvic acid
C) Lactic acid
D) NADH
Answer: B) Pyruvic acid
Explanation:
Glycolysis converts glucose into two molecules of pyruvic acid.
Question-19 Which enzyme catalyzes the conversion of pyruvate to Acetyl CoA?
A) Pyruvate kinase
B) Pyruvate dehydrogenase
C) ATP synthase
D) Succinyl CoA synthetase
Answer: B) Pyruvate dehydrogenase
Explanation:
Pyruvate dehydrogenase converts pyruvate to Acetyl CoA in the mitochondria.
Question-20 How many ATP molecules are produced from one NADH in the ETC?
A) 1
B) 2
C) 3
D) 4
Answer: C) 3
Explanation:
Each NADH contributes to the production of 3 ATP molecules.
Question-21 The process of fusion of male and female gametes is called:
A) Gametogenesis
B) Pollination
C) Fertilization
D) Sporogenesis
Answer: C) Fertilization
Explanation:
Fertilization is the process of the fusion of male and female gametes to form a zygote.
Question-22 Which part of the flower contains male reproductive organs?
A) Corolla
B) Calyx
C) Androecium
D) Gynoecium
Answer: C) Androecium
Explanation:
The androecium consists of stamens (anther and filament), which produce pollen grains containing male gametes.
Question-23 Which of the following is a unisexual flower?
A) Rose
B) Hibiscus
C) Papaya
D) Sunflower
Answer: C) Papaya
Explanation:
Unisexual flowers have either male or female reproductive structures. Papaya produces separate male and female flowers.
Question-24 What is the common term for microspore in angiosperms?
A) Ovule
B) Pollen grain
C) Embryo sac
D) Megaspore
Answer: B) Pollen grain
Explanation:
In angiosperms, the microspore develops into a pollen grain, which contains the male gametophyte.
Question-25 Where does pollen grain germinate?
A) Ovule
B) Stigma
C) Anther
D) Style
Answer: B) Stigma
Explanation:
When pollen lands on the stigma of a flower, it germinates to form a pollen tube for fertilization.
Question-26 Where does fertilization occur in humans?
A) Ovary
B) Uterus
C) Vagina
D) Fallopian tube
Answer: D) Fallopian tube
Explanation:
Fertilization typically occurs in the ampulla region of the fallopian tube.
Question-27 Which hormone triggers ovulation?
A) FSH
B) LH
C) Estrogen
D) Progesterone
Answer: B) LH
Explanation:
Luteinizing hormone (LH) surge triggers ovulation, releasing the secondary oocyte from the ovary.
Question-28 Which part of the sperm contains enzymes for penetrating the egg?
A) Middle piece
B) Tail
C) Acrosome
D) Nucleus
Answer: C) Acrosome
Explanation:
The acrosome, located at the sperm’s head, contains enzymes that help penetrate the egg’s outer layers.
Question-29 The hormone responsible for maintaining pregnancy is:
A) FSH
B) Progesterone
C) LH
D) Oxytocin
Answer: B) Progesterone
Explanation:
Progesterone maintains the uterine lining and prevents contractions during pregnancy.
Question-30 What is the function of the placenta?
A) Produces sperm
B) Produces milk
C) Supplies oxygen and nutrients to the fetus
D) Triggers ovulation
Answer: C) Supplies oxygen and nutrients to the fetus
Explanation:
The placenta facilitates nutrient and gas exchange between the mother and fetus.
Question-31 The genotypic ratio of a monohybrid cross in F₂ generation is:
A) 3:1
B) 9:3:3:1
C) 1:2:1
D) 2:2
Answer: C) 1:2:1
Explanation:
The genotypic ratio in F₂ generation is 1 homozygous dominant (TT) : 2 heterozygous (Tt) : 1 homozygous recessive (tt).
Question-32 Which of the following is an example of incomplete dominance?
A) Blood group inheritance
B) Flower color in Mirabilis jalapa
C) Seed shape in pea plants
D) Height in humans
Answer: B) Flower color in Mirabilis jalapa
Explanation:
In Mirabilis jalapa (Four O’Clock plant) , crossing red and white flowers produces pink flowers in F₁ generation, showing incomplete dominance.
Question-33 Which scientist proposed the Chromosomal Theory of Inheritance?
A) Gregor Mendel
B) Hugo de Vries
C) Sutton and Boveri
D) Watson and Crick
Answer: C) Sutton and Boveri
Explanation:
They proposed that genes are carried on chromosomes, explaining how traits are inherited.
Question-34 What is a test cross used for?
A) Determining phenotype
B) Identifying unknown genotype
C) Studying mutations
D) Producing hybrids
Answer: B) Identifying unknown genotype
Explanation:
A test cross involves crossing an individual with an unknown genotype with a homozygous recessive individual.
Question-35 What is the phenotypic ratio in a dihybrid cross in F₂ generation?
A) 9:3:3:1
B) 3:1
C) 1:2:1
D) 2:2
Answer: A) 9:3:3:1
Explanation:
In a dihybrid cross involving two contrasting traits, the phenotypic ratio in the F₂ generation is 9 dominant-dominant: 3 dominant-recessive: 3 recessive-dominant: 1 recessive-recessive.
Question-36 What is the full form of VNTRs used in DNA fingerprinting?
A) Variable Nucleotide Tandem Repeats
B) Variable Number of Tandem Repeats
C) Verified Nucleotide Transcription Regions
D) Variant Nucleosome Tertiary Regions
Answer: B) Variable Number of Tandem Repeats
Explanation:
VNTRs are short DNA sequences repeated multiple times , unique to individuals, making them useful in forensic analysis .
Question-37 Which enzyme is responsible for unwinding the DNA helix?
A) DNA polymerase
B) RNA polymerase
C) DNA helicase
D) DNA ligase
Answer: C) DNA helicase
Explanation:
DNA helicase breaks hydrogen bonds , separating the two DNA strands for replication.
Question-38 What is the direction of DNA synthesis?
A) 3’ to 5’
B) 5’ to 3’
C) 3’ to 3’
D) 5’ to 5’
Answer: B) 5’ to 3’
Explanation:
DNA polymerase adds nucleotides in the 5′ to 3′ direction during replication.
Question-39 Okazaki fragments are formed during DNA replication on:
A) Leading strand
B) Lagging strand
C) Both strands
D) RNA strand
Answer: B) Lagging strand
Explanation:
Okazaki fragments are short DNA sequences synthesized discontinuously on the lagging strand.
Question-40 Which nitrogenous base is present in RNA but not in DNA?
A) Adenine
B) Thymine
C) Uracil
D) Cytosine
Answer: C) Uracil
Explanation:
RNA has uracil (U) instead of thymine (T) , pairing with adenine.
Question-41 Which gas was absent in the primitive atmosphere of Earth?
A) Hydrogen
B) Oxygen
C) Methane
D) Ammonia
Answer: B) Oxygen
Explanation:
The early atmosphere was reducing and lacked free oxygen.
Question-42 The ‘RNA World Hypothesis’ suggests that:
A) Proteins were the first genetic material
B) RNA was the first self-replicating molecule
C) DNA and RNA coexisted from the beginning
D) Life originated in hydrothermal vents
Answer: B) RNA was the first self-replicating molecule
Explanation:
RNA was the first genetic material with catalytic properties , supporting the RNA World Hypothesis .
Question-43 Which scientist proposed the “Theory of Natural Selection”?
A) Gregor Mendel
B) Charles Darwin
C) Hugo de Vries
D) Lamarck
Answer: B) Charles Darwin
Explanation:
Darwin’s Theory of Natural Selection explains how favorable traits increase an organism’s survival chances.
Question-44 The finches observed by Darwin in the Galápagos Islands are an example of:
A) Adaptive Radiation
B) Convergent Evolution
C) Genetic Drift
D) Gene Flow
Answer: A) Adaptive Radiation
Explanation:
Darwin’s finches evolved different beak shapes to adapt to various ecological niches.
Question-45 Which of the following best describes industrial melanism?
A) Example of convergent evolution
B) Example of directional selection
C) Example of stabilizing selection
D) Example of artificial selection
Answer: B) Example of directional selection
Explanation:
The increase in black moths after industrialization is an example of natural selection favoring a specific trait .
Question-46 What is the movement of molecules from high to low concentration called?
A) Osmosis
B) Diffusion
C) Active transport
D) Imbibition
Answer: B) Diffusion
Explanation:
Diffusion is the passive movement of molecules from a region of higher concentration to lower concentration .
Question-47 The term ‘Diffusion Pressure Deficit’ (DPD) was coined by:
A) Mendel
B) B.S. Meyer
C) Charles Darwin
D) Watson and Crick
Answer: B) B.S. Meyer
Explanation:
B.S. Meyer coined the term DPD , which refers to the thirst of a cell for water.
Question-48 The process by which water enters the cytoplasm of root hair cells is:
A) Diffusion
B) Active transport
C) Osmosis
D) Imbibition
Answer: C) Osmosis
Explanation:
Osmosis is the movement of water through a semi-permeable membrane into root cells.
Question-49 What happens when a plant cell is placed in a hypertonic solution?
A) Turgidity increases
B) Plasmolysis occurs
C) Cell absorbs water
D) Imbibition takes place
Answer: B) Plasmolysis occurs
Explanation:
In a hypertonic solution , water leaves the cell, causing plasmolysis , where the protoplast shrinks.
Question-50 Which type of water potential does pure water have?
A) Zero
B) Positive
C) Negative
D) Infinite
Answer: A) Zero
Explanation:
Pure water has zero water potential , and any solute addition decreases its potential.
Question-51 What is the function of lateral meristem?
A) Increase in length
B) Increase in girth
C) Formation of new leaves
D) Production of flowers
Answer: B) Increase in girth
Explanation:
Lateral meristem (e.g., vascular cambium ) is responsible for secondary growth , increasing stem thickness
Question-52 Which method is used to measure linear growth of a plant?
A) Spectrophotometer
B) Auxanometer
C) Respirometer
D) Hygrometer
Answer: B) Auxanometer
Explanation:
Auxanometer is used to measure linear growth of a shoot .
Question-53 Which of the following elements is a macronutrient?
A) Zinc
B) Copper
C) Magnesium
D) Molybdenum
Answer: C) Magnesium
Explanation:
Macronutrients are required in large amounts . Mg is essential for chlorophyll synthesis .
Question-54 Which mineral is essential for nitrogen fixation?
A) Iron
B) Boron
C) Manganese
D) Molybdenum
Answer: D) Molybdenum
Explanation:
Molybdenum (Mo) is required for enzymes involved in biological nitrogen fixation .
Question-55 What is the function of potassium in plants?
A) Activation of enzymes
B) Component of chlorophyll
C) Helps in nitrogen fixation
D) Regulates stomatal opening
Answer: D) Regulates stomatal opening
Explanation:
Potassium (K) controls stomatal movement by regulating guard cell turgor pressure .
Question-56 The total lung capacity in an average adult human is approximately:
A) 1000 mL
B) 2500 mL
C) 5000-5800 mL
D) 10000 mL
Answer: C) 5000-5800 mL
Explanation:
Total lung capacity refers to the maximum volume of air the lungs can hold after a maximum inspiration .
Question-57 What is tidal volume?
A) Total amount of air in the lungs
B) Air inspired or expired during normal breathing
C) Extra air inhaled during deep breathing
D) Residual air left in the lungs
Answer: B) Air inspired or expired during normal breathing
Explanation:
Tidal volume (TV) is the volume of air exchanged in a normal breath (approx. 500 mL ).
Question-58 What is the primary driving force for gaseous exchange in alveoli?
A) Active transport
B) Diffusion
C) Osmosis
D) Filtration
Answer: B) Diffusion
Explanation:
Gases move from higher to lower partial pressure via diffusion across the alveolar membrane.
Question-59 Which part of the brain regulates breathing?
A) Cerebellum
B) Medulla oblongata
C) Cerebrum
D) Hypothalamus
Answer: B) Medulla oblongata
Explanation:
The medulla oblongata controls the rate and depth of breathing.
Question-60 What is the normal heart rate in a resting adult?
A) 50-55 beats per minute
B) 70-72 beats per minute
C) 90-100 beats per minute
D) 110-120 beats per minute
Answer: B) 70-72 beats per minute
Explanation:
The average heart rate in a resting adult is 70-72 beats per minute .
Question-61 What is the function of the cerebellum?
A) Thinking and memory
B) Coordination of voluntary movements
C) Regulation of body temperature
D) Controlling hunger and thirst
Answer: B) Coordination of voluntary movements
Explanation:
The cerebellum helps in maintaining balance and coordinating voluntary movements .
Question-62 The functional connection between two neurons is called:
A) Myelin sheath
B) Synapse
C) Ganglion
D) Axon hillock
Answer: B) Synapse
Explanation:
A synapse is the junction where nerve impulses pass from one neuron to another.
Question-63 What is the function of neurotransmitters?
A) Carry oxygen to neurons
B) Provide energy to neurons
C) Transmit nerve signals across synapses
D) Protect the neurons from damage
Answer: C) Transmit nerve signals across synapses
Explanation:
Neurotransmitters (e.g., acetylcholine) transmit nerve impulses across the synapse .
Question-64 Which part of the brain is responsible for emotions and memory?
A) Cerebellum
B) Medulla oblongata
C) Limbic system
D) Pons
Answer: C) Limbic system
Explanation:
The limbic system regulates emotions, memory, and behavior .
Question-65 The autonomic nervous system (ANS) controls:
A) Voluntary muscle movements
B) Involuntary functions like digestion and heartbeat
C) Thinking and memory
D) Reflex actions
Answer: B) Involuntary functions like digestion and heartbeat
Explanation:
The ANS regulates involuntary actions , including digestion, heart rate, and gland secretion.
Question-66 What type of immunity is provided by vaccination?
A) Innate immunity
B) Passive immunity
C) Active immunity
D) Cellular immunity
Answer: C) Active immunity
Explanation:
Vaccines stimulate the immune system to produce long-term active immunity .
Question-67 Which disease is caused by Plasmodium?
A) Dengue
B) Malaria
C) Filariasis
D) Typhoid
Answer: B) Malaria
Explanation:
Malaria is caused by Plasmodium and transmitted by female Anopheles mosquito .
Question-68 The vector for malaria is:
A) Culex mosquito
B) Aedes mosquito
C) Anopheles mosquito
D) Sandfly
Answer: C) Anopheles mosquito
Explanation:
Female Anopheles mosquitoes transmit malaria by carrying Plasmodium .
Question-69 Which cells perform phagocytosis to destroy pathogens?
A) B-cells
B) T-cells
C) Macrophages
D) Erythrocytes
Answer: C) Macrophages
Explanation:
Macrophages are immune cells that engulf and digest pathogens through phagocytosis .
Question-70 The Widal test is used to diagnose:
A) Malaria
B) Typhoid
C) Tuberculosis
D) Pneumonia
Answer: B) Typhoid
Explanation:
The Widal test detects Salmonella typhi antibodies in typhoid patients.
Question-71 What is the purpose of tissue culture in agriculture?
A) Genetic modification of animals
B) Rapid multiplication of disease-free plants
C) Improving soil fertility
D) Controlling insect pests
Answer: B) Rapid multiplication of disease-free plants
Explanation:
Tissue culture allows the mass production of identical, disease-free plants from a single cell.
Question-72 Which of the following is a high-yielding wheat variety?
A) Sonalika
B) IR8
C) Ratna
D) Jaya
Answer: A) Sonalika
Explanation:
Sonalika and Kalyan Sona were high-yielding wheat varieties introduced in India.
Question-73 Which scientist developed semi-dwarf wheat varieties?
A) Norman Borlaug
B) M.S. Swaminathan
C) Gregor Mendel
D) Hugo de Vries
Answer: A) Norman Borlaug
Explanation:
Norman Borlaug developed semi-dwarf wheat varieties , which significantly increased wheat production.
Question-74 Which plant hormone is responsible for stem elongation and fruit growth?
A) Auxin
B) Cytokinin
C) Gibberellin
D) Ethylene
Answer: C) Gibberellin
Explanation:
Gibberellins promote stem elongation, seed germination, and fruit growth .
Question-75 What is biofortification?
A) Increasing crop resistance to pests
B) Improving soil fertility
C) Enhancing nutritional value of crops
D) Crossbreeding different plant species
Answer: C) Enhancing nutritional value of crops
Explanation:
Biofortification is a breeding technique to increase vitamins, minerals, and protein in crops.
Question-76 Which organism is most commonly used as a cloning host in biotechnology?
A) Saccharomyces cerevisiae
B) Escherichia coli
C) Bacillus thuringiensis
D) Agrobacterium tumefaciens
Answer: B) Escherichia coli
Explanation:
E. coli is widely used in rDNA experiments due to its fast growth and ease of genetic manipulation .
Question-77 What is the role of Taq polymerase in PCR?
A) DNA degradation
B) DNA amplification
C) RNA synthesis
D) Ligating DNA fragments
Answer: B) DNA amplification
Explanation:
Taq polymerase is a heat-stable enzyme used in PCR to extend DNA strands .
Question-78 The Ti plasmid used for genetic transformation in plants is derived from:
A) Escherichia coli
B) Agrobacterium tumefaciens
C) Bacillus thuringiensis
D) Pseudomonas fluorescens
Answer: B) Agrobacterium tumefaciens
Explanation:
The Ti plasmid from Agrobacterium tumefaciens is used for gene transfer in plants .
Question-79 Which restriction enzyme produces sticky ends?
A) EcoRI
B) AluI
C) HindII
D) HaeIII
Answer: A) EcoRI
Explanation:
EcoRI recognizes GAATTC and produces sticky ends for DNA recombination.
Question-80 Golden rice is genetically modified to produce:
A) Iron
B) Vitamin A
C) Vitamin C
D) Protein
Answer: B) Vitamin A
Explanation:
Golden rice contains β-carotene , a precursor of Vitamin A , to prevent Vitamin A deficiency .
Question-81 A stenothermal organism can:
A) Tolerate a wide range of temperatures
B) Survive in extreme salinity conditions
C) Tolerate only a narrow temperature range
D) Exist in different types of habitats
Answer: C) Tolerate only a narrow temperature range
Explanation:
Stenothermal organisms can survive only in a limited temperature range .
Question-82 What is the role of homeostasis in organisms?
A) To prevent evolution
B) To maintain a constant internal environment
C) To promote mutation
D) To increase body size
Answer: B) To maintain a constant internal environment
Explanation:
Homeostasis helps organisms regulate body conditions despite external environmental changes.
Question-83 Desert plants use which type of photosynthesis to conserve water?
A) C3
B) C4
C) CAM
D) Calvin cycle
Answer: C) CAM
Explanation:
Crassulacean Acid Metabolism (CAM) allows desert plants to reduce water loss by keeping stomata closed during the day .
Question-84 The total dry weight of all organisms in a given area is called:
A) Population density
B) Biomass
C) Carrying capacity
D) Growth rate
Answer: B) Biomass
Explanation:
Biomass is the total dry weight of organisms in an area, used to estimate population productivity.
Question-85 What does the term “euryhaline” refer to?
A) Organisms that tolerate a narrow range of salinity
B) Organisms that tolerate a wide range of salinity
C) Organisms that migrate seasonally
D) Organisms that live in freshwater only
Answer: B) Organisms that tolerate a wide range of salinity
Explanation:
Euryhaline organisms can survive in both freshwater and saltwater environments .
Question-86 Which process is responsible for the breakdown of organic material in ecosystems?
A) Productivity
B) Decomposition
C) Energy flow
D) Zonation
Answer: B) Decomposition
Explanation:
Decomposers (bacteria and fungi) break down organic matter into simpler substances, releasing nutrients.
Question-87 What is the role of detritivores in decomposition?
A) Photosynthesis
B) Fragmentation of detritus
C) Nutrient absorption
D) Energy production
Answer: B) Fragmentation of detritus
Explanation:
Detritivores (e.g., earthworms, termites) break detritus into smaller particles , aiding decomposition.
Question-88 What is the primary source of energy in an ecosystem?
A) Decomposers
B) Sunlight
C) Carnivores
D) Oxygen
Answer: B) Sunlight
Explanation:
The Sun provides solar energy used by autotrophs (plants) for photosynthesis .
Question-89 Energy flow in an ecosystem is:
A) Bidirectional
B) Cyclic
C) Unidirectional
D) Reversible
Answer: C) Unidirectional
Explanation:
Energy flows in one direction , from producers to consumers , with some lost as heat at each trophic level.
Question-90 The 10% law of energy transfer was given by:
A) Charles Darwin
B) Raymond Lindeman
C) Gregor Mendel
D) Alfred Wallace
Answer: B) Raymond Lindeman
Explanation:
The 10% law (Lindeman, 1942) states that only 10% of energy is passed to the next trophic level.
Question-91 Which of the following is an example of ex-situ conservation?
A) National parks
B) Biosphere reserves
C) Botanical gardens
D) Wildlife sanctuaries
Answer: C) Botanical gardens
Explanation:
Ex-situ conservation involves protecting species outside their natural habitat , such as in zoos and botanical gardens .
Question-92 The term “Biosphere Reserve” refers to:
A) Areas for industrial use
B) Regions protected for conservation and research
C) Zones for urban development
D) Areas for agriculture expansion
Answer: B) Regions protected for conservation and research
Explanation:
Biosphere reserves are designated areas for conserving biodiversity and supporting research .
Question-93 Which of the following is NOT a biodiversity hotspot in India?
A) Western Ghats
B) Indo-Burma region
C) Amazon Rainforest
D) Eastern Himalayas
Answer: C) Amazon Rainforest
Explanation:
India has four biodiversity hotspots — Western Ghats, Himalayas, Indo-Burma, and Sundaland .
Question-94 Which organization maintains the Red Data Book?
A) WWF
B) IUCN
C) UNEP
D) UNESCO
Answer: B) IUCN
Explanation:
The International Union for Conservation of Nature (IUCN) maintains the Red Data Book , listing endangered species.
Question-95 The Evil Quartet refers to:
A) Four major pollutants
B) Four causes of biodiversity loss
C) Four endangered species
D) Four types of conservation strategies
Answer: B) Four causes of biodiversity loss
Explanation:
The Evil Quartet includes habitat loss, overexploitation, alien species invasion, and co-extinction .
Question-96 What is the purpose of Bt cotton?
A) High yield
B) Pest resistance
C) Drought resistance
D) Disease resistance
Answer: B) Pest resistance
Explanation:
Bt cotton produces Cry proteins from Bacillus thuringiensis , toxic to insect pests .
Question-97 The right side of the human heart contains:
A) Oxygenated blood
B) Deoxygenated blood
C) Lymph
D) Both oxygenated and deoxygenated blood
Answer: B) Deoxygenated blood
Explanation:
The right atrium and right ventricle receive and pump deoxygenated blood to the lungs.
Question-98 What is the meaning of “Survival of the Fittest”?
A) Only the strongest individuals survive
B) Organisms best adapted to their environment survive and reproduce
C) Evolution is a fast process
D) The largest species always survive
Answer: B) Organisms best adapted to their environment survive and reproduce
Explanation:
Darwin’s Natural Selection favors organisms with traits that improve survival and reproduction.
Question-99 The first menstrual cycle in females is called:
A) Menopause
B) Ovulation
C) Menarche
D) Luteal phase
Answer: C) Menarche
Explanation:
Menarche is the onset of the first menstrual cycle, marking the beginning of reproductive maturity.
Question-100 Where does the Krebs cycle take place?
A) Cytoplasm
B) Mitochondrial matrix
C) Inner mitochondrial membrane
D) Nucleus
Answer: B) Mitochondrial matrix
Explanation:
The Krebs cycle occurs in the mitochondrial matrix and generates energy.