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Question-1 Which enzyme is responsible for DNA replication?
a) DNA polymerase
b) RNA polymerase
c) Amylase
d) Ligase
Answer: a) DNA polymerase
Explanation:
DNA polymerase synthesizes new DNA strands during replication.
Question-2 What is the main function of ribosomal RNA (rRNA)?
a) Carries amino acids
b) Forms ribosomes
c) Transports genetic information
d) Catalyzes DNA replication
Answer: b) Forms ribosomes
Explanation:
rRNA, along with proteins, forms the structure of ribosomes, where protein synthesis occurs.
Question-3 Which enzyme model explains how enzymes slightly change shape upon substrate binding?
a) Lock and Key Model
b) Induced Fit Model
c) Competitive Inhibition Model
d) Allosteric Model
Answer: b) Induced Fit Model
Explanation:
The Induced Fit Model suggests that enzymes adjust their shape to better accommodate substrates.
Question-4 What is the role of ATP in metabolism?
a) Stores genetic information
b) Provides energy for cellular processes
c) Acts as a structural component of cells
d) Functions as an enzyme
Answer: b) Provides energy for cellular processes
Explanation:
ATP is the primary energy carrier in cells.
Question-5 Which type of RNA carries amino acids to the ribosome during protein synthesis?
a) mRNA
b) tRNA
c) rRNA
d) snRNA
Answer: b) tRNA
Explanation:
Transfer RNA (tRNA) binds to specific amino acids and carries them to ribosomes for protein synthesis.
Question-6 What is the pH range of normal urine?
A) 1-3
B) 4.5-8
C) 9-12
D) 12-14
Answer: B) 4.5-8
Explanation:
Urine pH varies between 4.5 and 8, depending on diet, hydration, and metabolic activity.
Question-7 Which kidney disorder is caused by the accumulation of uric acid crystals in joints?
A) Nephritis
B) Kidney stones
C) Gout
D) Uremia
Answer: C) Gout
Explanation:
Gout is caused by excess uric acid crystallizing in joints, leading to inflammation and pain.
Question-8 Which one of the following is a guanotelic organism?
A) Humans
B) Birds
C) Spiders
D) Frogs
Answer: C) Spiders
Explanation:
Spiders and scorpions excrete guanine instead of urea or uric acid, a process known as guanotelism.
Question-9 What is the normal blood urea level in humans?
A) 0.01 – 0.03%
B) 1 – 5%
C) 10 – 15%
D) 20 – 25%
Answer: A) 0.01 – 0.03%
Explanation:
The normal blood urea level is maintained within 0.01 – 0.03%. A rise beyond this can indicate kidney dysfunction.
Question-10 In which region of the nephron does selective reabsorption occur?
A) Bowman’s capsule
B) Proximal convoluted tubule
C) Collecting duct
D) Minor calyx
Answer: B) Proximal convoluted tubule
Explanation:
The proximal convoluted tubule reabsorbs essential nutrients like glucose, amino acids, and water back into the blood.
Question-11 What is the role of the enzyme lactase?
A) Breaks down lipids
B) Converts maltose into glucose
C) Digests lactose into glucose and galactose
D) Converts starch into maltose
Answer: C) Digests lactose into glucose and galactose
Explanation:
Lactase breaks down lactose, the sugar found in milk, into glucose and galactose.
Question-12 Which organ is responsible for producing bile?
A) Pancreas
B) Liver
C) Stomach
D) Small intestine
Answer: B) Liver
Explanation:
The liver produces bile, which is stored in the gallbladder and helps in fat digestion.
Question-13 Which of the following is a fat-soluble vitamin?
A) Vitamin C
B) Vitamin B12
C) Vitamin D
D) Vitamin B6
Answer: C) Vitamin D
Explanation:
Fat-soluble vitamins (A, D, E, K) are stored in body fat and require fats for absorption.
Question-14 Which part of the digestive system prevents acid reflux?
A) Pyloric sphincter
B) Cardiac sphincter
C) Epiglottis
D) Rectum
Answer: B) Cardiac sphincter
Explanation:
The cardiac sphincter prevents the backflow of stomach acids into the esophagus.
Question-15 Which digestive enzyme is secreted in an inactive form?
A) Trypsin
B) Amylase
C) Maltase
D) Lipase
Answer: A) Trypsin
Explanation:
Trypsin is secreted as trypsinogen and gets activated by enterokinase in the small intestine.
Question-16 The respiratory quotient (RQ) for glucose is:
A) 0.7
B) 0.9
C) 1.0
D) 1.2
Answer: C) 1.0
Explanation:
RQ = CO₂ released / O₂ consumed, which is 1 for glucose.
Question-17 What happens in muscle cells during intense exercise?
A) ATP production stops
B) Alcoholic fermentation occurs
C) Lactic acid accumulates
D) Oxygen is not required
Answer: C) Lactic acid accumulates
Explanation:
Anaerobic respiration in muscles produces lactic acid, leading to fatigue.
Question-18 Which enzyme regulates the rate of glycolysis?
A) Hexokinase
B) Phosphofructokinase
C) Succinyl CoA synthetase
D) ATP synthase
Answer: B) Phosphofructokinase
Explanation:
Phosphofructokinase regulates glycolysis by controlling fructose-1,6-bisphosphate production.
Question-19 Which enzyme is responsible for the final transfer of electrons to oxygen in the electron transport chain?
A) Cytochrome b
B) Cytochrome C oxidase
C) ATP synthase
D) NADH dehydrogenase
Answer: B) Cytochrome C oxidase
Explanation:
Cytochrome C oxidase (Complex IV) transfers electrons to oxygen, forming water.
Question-20 How many ATP molecules are produced by oxidative phosphorylation per glucose molecule?
A) 2
B) 4
C) 34
D) 38
Answer: C) 34
Explanation:
Oxidative phosphorylation generates the majority of ATP, with around 34 ATP per glucose.
Question-21 What is the function of the pollen tube?
A) Protects ovule
B) Delivers male gamete to ovule
C) Stores nutrients
D) Develops into fruit
Answer: B) Delivers male gamete to ovule
Explanation:
The pollen tube carries male gametes from the stigma to the ovule for fertilization.
Question-22 Which of the following structures develops into a fruit?
A) Ovule
B) Ovary
C) Anther
D) Stigma
Answer: B) Ovary
Explanation:
After fertilization, the ovary develops into a fruit that contains seeds.
Question-23 Which process results in the formation of two male gametes in pollen?
A) Mitosis
B) Meiosis
C) Fertilization
D) Pollination
Answer: A) Mitosis
Explanation:
The generative cell in pollen undergoes mitosis to produce two male gametes.
Question-24 The fertilization process in angiosperms is termed as:
A) Simple fertilization
B) Double fertilization
C) Cross fertilization
D) Multiple fertilization
Answer: B) Double fertilization
Explanation:
Angiosperms undergo double fertilization, where one male gamete fuses with the egg (forming a zygote), and the other fuses with polar nuclei (forming endosperm).
Question-25 What is the function of synergids in the embryo sac?
A) Produce pollen grains
B) Nourish the developing embryo
C) Guide pollen tube to the egg cell
D) Form the zygote
Answer: C) Guide pollen tube to the egg cell
Explanation:
Synergids help in directing the pollen tube toward the egg cell for fertilization.
Question-26 Which phase of the menstrual cycle involves the rebuilding of the endometrial lining?
A) Menstrual phase
B) Follicular phase
C) Luteal phase
D) Ovulatory phase
Answer: B) Follicular phase
Explanation:
The follicular phase (proliferative phase) is characterized by the regeneration of the endometrial lining under the influence of estrogen.
Question-27 Which hormone is responsible for milk ejection during lactation?
A) Estrogen
B) Progesterone
C) Oxytocin
D) Prolactin
Answer: C) Oxytocin
Explanation:
Oxytocin stimulates the contraction of mammary ducts, leading to milk ejection.
Question-28 Which part of the sperm contains mitochondria for energy production?
A) Head
B) Acrosome
C) Middle piece
D) Tail
Answer: C) Middle piece
Explanation:
The middle piece of sperm contains mitochondria, which generate ATP for motility.
Question-29 What is the primary function of the corpus luteum?
A) To store eggs
B) To secrete progesterone
C) To initiate menstruation
D) To trigger ovulation
Answer: B) To secrete progesterone
Explanation:
The corpus luteum secretes progesterone, which helps maintain the uterine lining for pregnancy.
Question-30 What is the significance of capacitation in sperm?
A) It activates sperm motility and fertilizing ability
B) It allows sperm to produce testosterone
C) It helps sperm attach to the uterine wall
D) It provides nourishment to the sperm
Answer: A) It activates sperm motility and fertilizing ability
Explanation:
Capacitation is the physiological change sperm undergo to penetrate and fertilize the egg.
Question-31 In a cross between a red-flowered (RR) and white-flowered (rr) plant, the F₁ generation has pink flowers. What is this an example of?
A) Codominance
B) Incomplete dominance
C) Multiple allelism
D) Pleiotropy
Answer: B) Incomplete dominance
Explanation:
In incomplete dominance , neither allele is completely dominant, leading to an intermediate phenotype (pink flowers in this case).
Question-32 The presence of more than two alleles for a gene in a population is called:
A) Pleiotropy
B) Codominance
C) Multiple allelism
D) Epistasis
Answer: C) Multiple allelism
Explanation:
Multiple allelism refers to genes that have more than two allelic forms, such as the ABO blood group system.
Question-33 Which type of chromosomal mutation leads to Down’s Syndrome?
A) Monosomy
B) Trisomy
C) Translocation
D) Deletion
Answer: B) Trisomy
Explanation:
Down’s Syndrome is caused by trisomy of chromosome 21 , meaning an extra copy of chromosome 21 is present.
Question-34 In a dihybrid test cross, the expected phenotypic ratio is:
A) 9:3:3:1
B) 1:1:1:1
C) 3:1
D) 2:2
Answer: B) 1:1:1:1
Explanation:
In a dihybrid test cross , the heterozygous individual (TtYy) is crossed with a double recessive (ttyy), leading to a 1:1:1:1 ratio .
Question-35 The disorder caused by the absence of clotting factor VIII is:
A) Color blindness
B) Hemophilia A
C) Sickle cell anemia
D) Thalassemia
Answer: B) Hemophilia A
Explanation:
Hemophilia A is due to the absence of clotting factor VIII , leading to excessive bleeding.
Question-36 Which of the following is NOT a property of the genetic code?
A) Universal
B) Ambiguous
C) Degenerate
D) Non-overlapping
Answer: B) Ambiguous
Explanation:
The genetic code is unambiguous , meaning each codon specifies only one amino acid.
Question-37 Which type of RNA is involved in carrying amino acids to the ribosome during translation?
A) mRNA
B) tRNA
C) rRNA
D) snRNA
Answer: B) tRNA
Explanation:
Transfer RNA (tRNA) carries amino acids to ribosomes and matches them with codons on mRNA .
Question-38 Which sequence of DNA acts as a stop signal for transcription?
A) Start codon
B) Promoter
C) Terminator
D) Enhancer
Answer: C) Terminator
Explanation:
The terminator sequence signals RNA polymerase to stop transcription .
Question-39 Which enzyme is responsible for transcription in prokaryotes?
A) DNA polymerase
B) RNA polymerase
C) DNA ligase
D) Helicase
Answer: B) RNA polymerase
Explanation:
RNA polymerase catalyzes the synthesis of RNA from a DNA template.
Question-40 In eukaryotes, where does transcription occur?
A) Cytoplasm
B) Ribosome
C) Nucleus
D) Mitochondria
Answer: C) Nucleus
Explanation:
Transcription occurs in the nucleus , while translation occurs in the cytoplasm .
Question-41 Which principle states that allele frequencies in a population remain constant unless acted upon by evolutionary forces?
A) Darwin’s Theory
B) Hardy-Weinberg Principle
C) Mutation Theory
D) Gene Flow Theory
Answer: B) Hardy-Weinberg Principle
Explanation:
The Hardy-Weinberg equilibrium describes a non-evolving population where allele frequencies remain unchanged.
Question-42 Which factor can disrupt Hardy-Weinberg equilibrium?
A) Large population size
B) Absence of mutations
C) Random mating
D) Natural selection
Answer: D) Natural selection
Explanation:
Natural selection alters allele frequencies by favoring traits that increase survival and reproduction.
Question-43 Which of the following is an example of allopatric speciation?
A) A single population splits due to a geographic barrier
B) Different species evolve within the same geographic region
C) Gene flow between populations increases
D) Hybridization between two species
Answer: A) A single population splits due to a geographic barrier
Explanation:
Allopatric speciation occurs when a physical barrier (mountains, rivers, etc.) separates populations, leading to speciation.
Question-44 Which type of speciation occurs without geographical isolation?
A) Allopatric speciation
B) Sympatric speciation
C) Parapatric speciation
D) Artificial speciation
Answer: B) Sympatric speciation
Explanation:
Sympatric speciation occurs when populations evolve into new species while living in the same geographic area .
Question-45 Which of the following is an example of homologous organs?
A) Wings of birds and insects
B) Flippers of whales and human arms
C) Eyes of octopus and humans
D) Fins of fish and legs of frogs
Answer: B) Flippers of whales and human arms
Explanation:
Homologous organs have similar structures but different functions , indicating a common ancestry .
Question-46 What regulates the opening and closing of stomata?
A) Water availability
B) Carbon dioxide concentration
C) Light intensity
D) All of the above
Answer: D) All of the above
Explanation:
Stomatal movement is controlled by water availability, CO₂ concentration, and light intensity .
Question-47 The transpiration rate increases when:
A) Humidity is high
B) Temperature is low
C) Wind speed is high
D) CO₂ concentration is high
Answer: C) Wind speed is high
Explanation:
Increased wind speed removes water vapor from leaf surfaces, increasing transpiration.
Question-48 Which of the following is a disadvantage of transpiration?
A) Loss of turgidity
B) Wilting
C) Excess water loss
D) All of the above
Answer: D) All of the above
Explanation:
Excessive transpiration causes wilting, turgor loss, and dehydration .
Question-49 What is the cohesion-tension theory?
A) Water moves passively due to osmosis
B) Water is pushed upwards by root pressure
C) Water molecules stick together, creating a pull
D) Water moves through active transport
Answer: C) Water molecules stick together, creating a pull
Explanation:
The cohesion-tension theory explains how hydrogen bonds between water molecules create a continuous water column in the xylem.
Question-50 Which plant hormone regulates stomatal closure during drought?
A) Auxin
B) Cytokinin
C) Gibberellin
D) Abscisic Acid (ABA)
Answer: D) Abscisic Acid (ABA)
Explanation:
ABA triggers stomatal closure to reduce water loss during drought .
Question-51 Which process is stimulated by gibberellins?
A) Flowering in long-day plants
B) Leaf abscission
C) Dormancy of seeds
D) Closing of stomata
Answer: A) Flowering in long-day plants
Explanation:
Gibberellins promote flowering in long-day plants and also help in breaking seed dormancy .
Question-52 The movement of a plant in response to a stimulus without reference to direction is called:
A) Tropism
B) Turgor movement
C) Nastic movement
D) Phototropism
Answer: C) Nastic movement
Explanation:
Nastic movements (e.g., folding of Mimosa pudica ) occur in response to stimuli but without a specific direction .
Question-53 Which hormone is responsible for fruit ripening?
A) Auxin
B) Gibberellin
C) Ethylene
D) Cytokinin
C) Ethylene
Explanation:
Ethylene controls fruit ripening, flower senescence, and leaf abscission .
Question-54 What is vernalization?
A) Promotion of flowering by exposure to cold
B) Growth inhibition by high temperature
C) Growth stimulation by blue light
D) Control of stomatal movement
Answer: A) Promotion of flowering by exposure to cold
Explanation:
Vernalization is a cold treatment that induces flowering in biennial plants .
Question-55 Which element is essential for the synthesis of auxin?
A) Zinc
B) Magnesium
C) Boron
D) Manganese
Answer: A) Zinc
Explanation:
Zinc is required for auxin (IAA) synthesis , which controls plant growth and elongation .
Question-56 Which blood component helps in clotting?
A) White blood cells
B) Red blood cells
C) Platelets
D) Plasma
Answer: C) Platelets
Explanation:
Platelets (thrombocytes) release clotting factors like thrombin and fibrinogen to stop bleeding.
Question-57 What is the pH of human blood?
A) 6.5
B) 7.4
C) 8.0
D) 5.5
Answer: B) 7.4
Explanation:
Normal blood pH is slightly alkaline (7.4) , maintaining homeostasis.
Question-58 Which blood vessel carries deoxygenated blood from the heart to the lungs?
A) Pulmonary artery
B) Pulmonary vein
C) Aorta
D) Coronary artery
Answer: A) Pulmonary artery
Explanation:
The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs .
Question-59 Which valve prevents the backflow of blood from the left ventricle to the left atrium?
A) Tricuspid valve
B) Pulmonary valve
C) Aortic valve
D) Bicuspid (mitral) valve
Answer: D) Bicuspid (mitral) valve
Explanation:
The bicuspid (mitral) valve prevents backflow of blood from the left ventricle to the left atrium .
Question-60 What is the main function of the coronary arteries?
A) Supply oxygen to the brain
B) Remove carbon dioxide from blood
C) Supply oxygen-rich blood to the heart
D) Transport waste materials
Answer: C) Supply oxygen-rich blood to the heart
Explanation:
Coronary arteries supply oxygenated blood to the heart muscle for its function.
Question-61 Which hormone regulates blood sugar levels?
A) Thyroxine
B) Insulin
C) Adrenaline
D) Growth hormone
Answer: B) Insulin
Explanation:
Insulin , secreted by the pancreas , helps in glucose uptake and regulates blood sugar levels.
Question-62 What is the function of the thyroid hormone thyroxine?
A) Controls metabolism
B) Stimulates milk production
C) Maintains blood calcium levels
D) Regulates heartbeat
Answer: A) Controls metabolism
Explanation:
Thyroxine (T4) regulates metabolism, growth, and energy balance .
Question-63 Which hormone is responsible for calcium regulation in the blood?
A) Thyroxine
B) Insulin
C) Parathyroid hormone
D) Glucagon
Answer: C) Parathyroid hormone
Explanation:
Parathyroid hormone (PTH) increases blood calcium levels by stimulating bone resorption.
Question-64 Which hormone is responsible for growth and development?
A) Insulin
B) Growth hormone (GH)
C) Estrogen
D) Oxytocin
Answer: B) Growth hormone (GH)
Explanation:
GH (Somatotropin) promotes growth, cell division, and protein synthesis .
Question-65 Which part of the nervous system prepares the body for emergency responses?
A) Sympathetic nervous system
B) Parasympathetic nervous system
C) Somatic nervous system
D) Central nervous system
Answer: A) Sympathetic nervous system
Explanation:
The sympathetic nervous system activates the fight or flight response , increasing heart rate and energy release.
Question-66 Which disease is caused by the deficiency of insulin?
A) Hypertension
B) Diabetes mellitus
C) Goitre
D) Rickets
Answer: B) Diabetes mellitus
Explanation:
Diabetes mellitus is caused by low insulin production or insulin resistance , leading to high blood sugar levels .
Question-67 Which of the following is an autoimmune disease?
A) Malaria
B) Tuberculosis
C) Rheumatoid arthritis
D) Typhoid
Answer: C) Rheumatoid arthritis
Explanation:
Rheumatoid arthritis occurs when the immune system attacks body tissues , causing joint inflammation .
Question-68 What is the mode of transmission of dengue fever?
A) Contaminated food
B) Mosquito bite
C) Airborne droplets
D) Direct contact
Answer: B) Mosquito bite
Explanation:
Dengue fever is transmitted by Aedes mosquitoes .
Question-69 Which organ is affected by hepatitis?
A) Lungs
B) Liver
C) Brain
D) Kidney
Answer: B) Liver
Explanation:
Hepatitis is the inflammation of the liver caused by viruses (Hepatitis A, B, C, etc.) .
Question-70 The BCG vaccine is used for preventing:
A) Polio
B) Tuberculosis
C) Hepatitis
D) Tetanus
Answer: B) Tuberculosis
Explanation:
The BCG vaccine (Bacillus Calmette-Guérin) provides protection against tuberculosis (TB).
Question-71 Apiculture is associated with the rearing of:
A) Fishes
B) Silkworms
C) Honeybees
D) Goats
Answer: C) Honeybees
Explanation:
Apiculture is the scientific rearing of honeybees for honey and wax production .
Question-72 Which species of honeybee is most commonly used in commercial honey production?
A) Apis dorsata
B) Apis indica
C) Apis mellifera
D) Apis florea
Answer: C) Apis mellifera
Explanation:
Apis mellifera (European honeybee) is widely used in commercial honey production due to its high yield.
Question-73 The term pisciculture refers to:
A) Cultivation of medicinal plants
B) Rearing of fish
C) Rearing of silk moths
D) Hybridization of crops
Answer: B) Rearing of fish
Explanation:
Pisciculture (fish farming) is the breeding, rearing, and harvesting of fish in controlled environments.
Question-74 Which of the following is an example of an edible fungus?
A) Penicillium
B) Rhizopus
C) Agaricus
D) Aspergillus
Answer: C) Agaricus
Explanation:
Agaricus bisporus is a commonly consumed mushroom .
Question-75 What is sericulture?
A) Rearing of silkworms for silk production
B) Rearing of fish
C) Production of organic fertilizers
D) Cultivation of seaweed
Answer: A) Rearing of silkworms for silk production
Explanation:
Sericulture is the rearing of silkworms (Bombyx mori) for silk extraction .
Question-76 Which enzyme is used to convert RNA into complementary DNA (cDNA)?
A) DNA polymerase
B) RNA polymerase
C) Reverse transcriptase
D) Ligase
Answer: C) Reverse transcriptase
Explanation:
Reverse transcriptase synthesizes cDNA from mRNA , useful in gene cloning and RT-PCR .
Question-77 What is the function of gene cloning?
A) Destruction of genes
B) Multiplication of specific genes
C) Production of mutations
D) Transcription inhibition
Answer: B) Multiplication of specific genes
Explanation:
Gene cloning allows scientists to create multiple identical copies of a particular gene for study or application.
Question-78 What is a transgenic organism?
A) An organism with only natural genes
B) An organism with genes from another species
C) An organism that cannot reproduce
D) An organism without DNA
Answer: B) An organism with genes from another species
Explanation:
Transgenic organisms contain foreign genes inserted through genetic engineering .
Question-79 The Human Genome Project (HGP) aimed to:
A) Sequence the entire human genome
B) Modify human DNA
C) Discover antibiotics
D) Improve agricultural crops
Answer: A) Sequence the entire human genome
Explanation:
The HGP (1990-2003) successfully mapped and sequenced all human genes .
Question-80 Which bacteria are commonly used in the production of human insulin?
A) Lactobacillus
B) Streptococcus
C) Escherichia coli
D) Bacillus subtilis
Answer: C) Escherichia coli
Explanation:
Recombinant human insulin (Humulin) is produced using genetically engineered E. coli .
Question-81 Which of the following is an example of commensalism?
A) Lichen (fungus and algae)
B) Barnacles on whales
C) Cattle egret and grazing cattle
D) Tapeworm in the intestine
Answer: C) Cattle egret and grazing cattle
Explanation:
Commensalism is a relationship where one species benefits while the other remains unaffected (e.g., cattle egrets feed on insects disturbed by grazing cattle).
Question-82 Which of the following is an example of amensalism?
A) Penicillium inhibiting bacterial growth
B) Lichen (fungus and algae)
C) Sea anemone and clownfish
D) Bee and flower
Answer: A) Penicillium inhibiting bacterial growth
Explanation:
Amensalism occurs when one species is harmed while the other is unaffected , like Penicillium releasing antibiotics that kill bacteria .
Question-83 Which of the following describes parasitism?
A) Both species benefit
B) One benefits, the other remains unaffected
C) One benefits at the expense of the other
D) Both species are harmed
Answer: C) One benefits at the expense of the other
Explanation:
In parasitism , one organism ( parasite ) benefits while the host suffers, like tapeworms in human intestines .
Question-84 What happens when a population reaches its carrying capacity?
A) Population growth accelerates
B) Birth rates decrease and death rates increase
C) The population goes extinct
D) The population undergoes exponential growth
Answer: B) Birth rates decrease and death rates increase
Explanation:
When a population reaches carrying capacity , resources become limited , slowing population growth.
Question-85 What type of interaction exists between a predator and its prey?
A) Mutualism
B) Parasitism
C) Exploitation
D) Commensalism
Answer: C) Exploitation
Explanation:
Predation is an exploitative relationship where one organism feeds on another .
Question-86 Which ecological pyramid is always upright?
A) Pyramid of biomass
B) Pyramid of numbers
C) Pyramid of energy
D) Pyramid of productivity
Answer: C) Pyramid of energy
Explanation:
Energy pyramids are always upright , as energy is lost at each trophic level.
Question-87 Which ecosystem has the highest productivity?
A) Desert
B) Open ocean
C) Tropical rainforest
D) Grassland
Answer: C) Tropical rainforest
Explanation:
Tropical rainforests have the highest Net Primary Productivity (NPP) due to warm temperatures and high rainfall .
Question-88 The rate of biomass production per unit area over time is called:
A) Ecological efficiency
B) Productivity
C) Carrying capacity
D) Energy flow
Answer: B) Productivity
Explanation:
Productivity refers to the rate of biomass formation per unit area per unit time.
Question-89 Which of the following represents a grazing food chain?
A) Dead leaves → Earthworms → Frogs → Snakes
B) Phytoplankton → Zooplankton → Fish → Shark
C) Fungi → Bacteria → Decomposers
D) Grass → Detritus → Earthworm → Bird
Answer: B) Phytoplankton → Zooplankton → Fish → Shark
Explanation:
Grazing food chains start with living plants (producers) consumed by herbivores .
Question-90 Which factor influences the rate of decomposition the most?
A) Soil color
B) pH of water
C) Temperature and moisture
D) Wind speed
Answer: C) Temperature and moisture
Explanation:
Warm, moist environments enhance decomposition , while extreme dryness or cold slows it down.
Question-91 Which of the following is NOT a cause of biodiversity loss?
A) Habitat destruction
B) Overexploitation
C) Sustainable development
D) Invasive species
Answer: C) Sustainable development
Explanation:
Sustainable development aims to balance economic growth and environmental protection , reducing biodiversity loss.
Question-92 Which conservation method involves protecting species in their natural habitat?
A) In-situ conservation
B) Ex-situ conservation
C) Gene banks
D) Tissue culture
Answer: A) In-situ conservation
Explanation:
In-situ conservation protects species within their natural ecosystem , e.g., national parks and wildlife sanctuaries .
Question-93 The Kyoto Protocol is associated with:
A) Wetland conservation
B) Climate change and greenhouse gases
C) Endangered species protection
D) Conservation of marine life
Answer: B) Climate change and greenhouse gases
Explanation:
The Kyoto Protocol (1997) focuses on reducing greenhouse gas emissions to combat climate change.
Question-94 Which of the following is a greenhouse gas?
A) Nitrogen
B) Oxygen
C) Carbon dioxide
D) Neon
Answer: C) Carbon dioxide
Explanation:
CO₂, CH₄, and N₂O are major greenhouse gases , leading to global warming.
Question-95 The Taj Mahal is affected by which environmental issue?
A) Acid rain
B) Ozone depletion
C) Desertification
D) Global warming
Answer: A) Acid rain
Explanation:
Acid rain (due to SO₂ and NO₂ emissions) reacts with marble, causing “Marble Cancer” on the Taj Mahal.
Question-96 The presence of albumin in urine indicates:
A) Normal kidney function
B) Kidney infection
C) High blood sugar levels
D) High hemoglobin levels
Answer: B) Kidney infection
Explanation: Albuminuria (albumin in urine) suggests kidney damage or infection, as proteins are not normally filtered into urine.
Question-97 What is the function of juxtaglomerular apparatus (JGA)?
A) Regulation of blood pressure
B) Filtration of urine
C) Absorption of urea
D) Synthesis of proteins
Answer: A) Regulation of blood pressure
Explanation:
JGA regulates blood pressure by releasing renin, which activates the RAAS (Renin-Angiotensin-Aldosterone System).
Question-98 Which hormone is responsible for sodium retention in the kidneys?
A) ADH
B) Aldosterone
C) Insulin
D) Oxytocin
Answer: B) Aldosterone
Explanation:
Aldosterone promotes sodium reabsorption in the distal convoluted tubule and collecting duct, helping in water retention.
Question-99 Which part of the seed is responsible for protecting the embryo?
A) Endosperm
B) Seed coat
C) Cotyledons
D) Plumule
Answer: B) Seed coat
Explanation:
The seed coat provides protection to the developing embryo from environmental stress.
Question-100 Which of the following mutations results in a change of one amino acid in the protein sequence?
A) Silent mutation
B) Missense mutation
C) Nonsense mutation
D) Frameshift mutation
Answer: B) Missense mutation
Explanation:
A missense mutation changes a single codon, leading to the incorporation of a different amino acid.