- Which process is responsible for the formation of gametes in animals?
(A) Mitosis
(B) Meiosis
(C) Binary fission
(D) Budding
Answer: (B)
Explanation: Meiosis is the process in animals that produces gametes (sperm and eggs) with half the chromosome number, ensuring genetic diversity. Mitosis produces identical body cells, binary fission occurs in bacteria, and budding is asexual reproduction. - What is the primary function of the small intestine in humans?
(A) Water absorption
(B) Nutrient absorption
(C) Protein synthesis
(D) Gas exchange
Answer: (B)
Explanation: The small intestine absorbs nutrients (e.g., glucose, amino acids) from digested food via its villi. Water absorption occurs mainly in the large intestine, protein synthesis in cells, and gas exchange in lungs. - Which gas, produced during photosynthesis, is essential for respiration?
(A) Carbon dioxide
(B) Oxygen
(C) Nitrogen
(D) Hydrogen
Answer: (B)
Explanation: Photosynthesis produces oxygen as a byproduct, which is essential for cellular respiration in animals and plants. - Which structure in the human ear amplifies sound vibrations?
(A) Cochlea
(B) Ossicles
(C) Eardrum
(D) Auditory nerve
Answer: (B)
Explanation: The ossicles (malleus, incus, stapes) in the middle ear amplify and transmit sound vibrations to the cochlea. - What is the term for the study of fungi?
(A) Mycology
(B) Phycology
(C) Bryology
(D) Ethology
Answer: (A)
Explanation: Mycology is the study of fungi, including their classification and ecology. - Which hormone is responsible for ovulation in females?
(A) Estrogen
(B) Progesterone
(C) Luteinizing hormone
(D) Oxytocin
Answer: (C)
Explanation: Luteinizing hormone (LH), secreted by the pituitary gland, triggers ovulation by causing the release of an egg from the ovary. - Which type of ecological interaction benefits both species?
(A) Parasitism
(B) Mutualism
(C) Commensalism
(D) Predation
Answer: (B)
Explanation: Mutualism is an interaction where both species benefit, e.g., bees pollinating flowers. - What is the primary source of energy for cellular respiration?
(A) Glucose
(B) Protein
(C) Lipid
(D) Nucleic acid
Answer: (A)
Explanation: Glucose is the primary substrate for cellular respiration, broken down to produce ATP. - Which part of a flower develops into a fruit?
(A) Stamen
(B) Petal
(C) Ovary
(D) Sepal
Answer: (C)
Explanation: The ovary, part of the pistil, develops into a fruit after fertilization, enclosing seeds. - What is the term for the loss of water vapor from plant leaves?
(A) Guttation
(B) Transpiration
(C) Exudation
(D) Evaporation
Answer: (B)
Explanation: Transpiration is the loss of water vapor through stomata in leaves, aiding nutrient transport. - Which blood vessel carries oxygenated blood from the lungs to the heart?
(A) Pulmonary artery
(B) Pulmonary vein
(C) Aorta
(D) Vena cava
Answer: (B)
Explanation: The pulmonary vein carries oxygenated blood from the lungs to the left atrium. - What is the study of animal behavior called?
(A) Ethology
(B) Ecology
(C) Zoology
(D) Ornithology
Answer: (A)
Explanation: Ethology studies animal behavior, focusing on instincts and learned actions. - Which enzyme breaks down starch into sugars?
(A) Lipase
(B) Amylase
(C) Protease
(D) Nuclease
Answer: (B)
Explanation: Amylase, found in saliva and pancreatic juice, breaks down starch into sugars like maltose. - Which type of reproduction involves fusion of gametes?
(A) Asexual reproduction
(B) Sexual reproduction
(C) Vegetative propagation
(D) Budding
Answer: (B)
Explanation: Sexual reproduction involves the fusion of male and female gametes, producing genetically diverse offspring. - What is the primary role of hemoglobin in blood?
(A) Clotting
(B) Immunity
(C) Oxygen transport
(D) Nutrient transport
Answer: (C)
Explanation: Hemoglobin in red blood cells binds and transports oxygen from lungs to tissues. - Which ecosystem has the highest biodiversity?
(A) Desert
(B) Tundra
(C) Tropical rainforest
(D) Grassland
Answer: (C)
Explanation: Tropical rainforests, with their warm climate and abundant resources, support the highest biodiversity. - What is the term for the process of cell division in somatic cells?
(A) Meiosis
(B) Mitosis
(C) Cytokinesis
(D) Binary fission
Answer: (B)
Explanation: Mitosis is the process of cell division in somatic (body) cells, producing two identical daughter cells. - Which organ stores bile in the human body?
(A) Pancreas
(B) Liver
(C) Gallbladder
(D) Stomach
Answer: (C)
Explanation: The gallbladder stores bile, produced by the liver, for fat digestion. - What is the term for the transfer of pollen from anther to stigma?
(A) Fertilization
(B) Pollination
(C) Germination
(D) Dispersal
Answer: (B)
Explanation: Pollination is the transfer of pollen from anther to stigma, enabling fertilization. - Which vitamin deficiency causes night blindness?
(A) Vitamin A
(B) Vitamin B1
(C) Vitamin C
(D) Vitamin D
Answer: (A)
Explanation: Vitamin A deficiency causes night blindness by impairing rhodopsin production in the retina. - Which part of the human brain controls balance and coordination?
(A) Cerebrum
(B) Cerebellum
(C) Medulla oblongata
(D) Hypothalamus
Answer: (B)
Explanation: The cerebellum regulates balance and coordination. - What is the primary source of nitrogen for plants?
(A) Air
(B) Soil
(C) Water
(D) Sunlight
Answer: (B)
Explanation: Plants absorb nitrogen (as nitrates or ammonium) from the soil, essential for protein synthesis. - Which type of RNA carries amino acids during protein synthesis?
(A) mRNA
(B) tRNA
(C) rRNA
(D) snRNA
Answer: (B)
Explanation: Transfer RNA (tRNA) carries amino acids to ribosomes during protein synthesis. - What is the term for the gradual change in species over time?
(A) Adaptation
(B) Evolution
(C) Mutation
(D) Speciation
Answer: (B)
Explanation: Evolution is the gradual change in species over generations, driven by mechanisms like natural selection. - Which hormone promotes fruit ripening?
(A) Auxin
(B) Gibberellin
(C) Ethylene
(D) Cytokinin
Answer: (C)
Explanation: Ethylene, a gaseous hormone, promotes fruit ripening. - Which structure in the kidney filters blood?
(A) Nephron
(B) Ureter
(C) Urethra
(D) Bladder
Answer: (A)
Explanation: The nephron, specifically the glomerulus, filters blood to form urine. - What is the term for the symbiotic relationship where one species benefits and the other is unaffected?
(A) Mutualism
(B) Commensalism
(C) Parasitism
(D) Competition
Answer: (B)
Explanation: Commensalism benefits one species while the other is neither harmed nor benefited. - Which disease is caused by a protozoan parasite?
(A) Tuberculosis
(B) Malaria
(C) Dengue
(D) Cholera
Answer: (B)
Explanation: Malaria is caused by the protozoan Plasmodium. - What is the primary function of stomata in plants?
(A) Nutrient absorption
(B) Gas exchange
(C) Water transport
(D) Photosynthesis
Answer: (B)
Explanation: Stomata, pores on leaves, facilitate gas exchange (carbon dioxide in, oxygen out) for photosynthesis and respiration. - Which genetic disorder is caused by an extra chromosome 21?
(A) Sickle cell anemia
(B) Down syndrome
(C) Cystic fibrosis
(D) Hemophilia
Answer: (B)
Explanation: Down syndrome results from trisomy 21 (an extra chromosome 21). - Which organ produces red blood cells in adults?
(A) Liver
(B) Spleen
(C) Bone marrow
(D) Kidney
Answer: (C)
Explanation: Bone marrow produces red blood cells in adults via hematopoiesis. - What is the term for the process of breaking down complex molecules into simpler ones?
(A) Anabolism
(B) Catabolism
(C) Metabolism
(D) Homeostasis
Answer: (B)
Explanation: Catabolism breaks down complex molecules (e.g., glucose) into simpler ones, releasing energy. - Which tissue connects muscles to bones?
(A) Ligament
(B) Tendon
(C) Cartilage
(D) Adipose tissue
Answer: (B)
Explanation: Tendons, made of connective tissue, attach muscles to bones. - What is the primary source of energy for Earth’s climate system?
(A) Geothermal heat
(B) Sun
(C) Fossil fuels
(D) Ocean currents
Answer: (B)
Explanation: The Sun drives Earth’s climate system through solar radiation. - Which molecule stores genetic information in viruses?
(A) DNA only
(B) RNA only
(C) DNA or RNA
(D) Proteins
Answer: (C)
Explanation: Viruses store genetic information in either DNA or RNA, depending on the virus type. - Which process converts atmospheric nitrogen into usable compounds for plants?
(A) Nitrification
(B) Denitrification
(C) Nitrogen fixation
(D) Ammonification
Answer: (C)
Explanation: Nitrogen fixation, performed by bacteria like Rhizobium, converts atmospheric nitrogen into ammonia for plant use. - Which part of the human eye controls the amount of light entering?
(A) Cornea
(B) Iris
(C) Lens
(D) Retina
Answer: (B)
Explanation: The iris adjusts the pupil size to control light entry. - What is the term for a group of ecosystems with similar climates and organisms?
(A) Habitat
(B) Biome
(C) Niche
(D) Community
Answer: (B)
Explanation: A biome is a large region with similar climate and organisms (e.g., deserts, forests). - Which hormone regulates water reabsorption in kidneys?
(A) Insulin
(B) Antidiuretic hormone
(C) Cortisol
(D) Thyroxine
Answer: (B)
Explanation: Antidiuretic hormone (ADH), secreted by the pituitary, promotes water reabsorption in kidneys to maintain fluid balance. - Which type of joint allows the widest range of motion?
(A) Hinge joint
(B) Pivot joint
(C) Ball-and-socket joint
(D) Suture joint
Answer: (C)
Explanation: Ball-and-socket joints (e.g., shoulder, hip) allow multidirectional movement. - What is the term for the process of sperm and egg fusion?
(A) Pollination
(B) Fertilization
(C) Germination
(D) Implantation
Answer: (B)
Explanation: Fertilization is the fusion of sperm and egg to form a zygote. - Which gas contributes to the greenhouse effect?
(A) Oxygen
(B) Nitrogen
(C) Carbon dioxide
(D) Argon
Answer: (C)
Explanation: Carbon dioxide traps heat, contributing to the greenhouse effect and global warming. - Which cell organelle is involved in detoxification?
(A) Ribosome
(B) Smooth endoplasmic reticulum
(C) Golgi apparatus
(D) Lysosome
Answer: (B)
Explanation: The smooth endoplasmic reticulum detoxifies drugs and toxins in cells, especially in the liver. - What is the term for the movement of water across a semi-permeable membrane?
(A) Diffusion
(B) Osmosis
(C) Active transport
(D) Facilitated diffusion
Answer: (B)
Explanation: Osmosis is the passive movement of water across a semi-permeable membrane from low to high solute concentration. - Which type of muscle is found in the walls of the heart?
(A) Skeletal muscle
(B) Cardiac muscle
(C) Smooth muscle
(D) Voluntary muscle
Answer: (B)
Explanation: Cardiac muscle is found only in the heart and is responsible for its rhythmic contractions. - Which vitamin is essential for calcium absorption?
(A) Vitamin A
(B) Vitamin B12
(C) Vitamin C
(D) Vitamin D
Answer: (D)
Explanation: Vitamin D promotes the absorption of calcium from the intestine, which is vital for healthy bones and teeth. - Which blood component is mainly responsible for clotting?
(A) Red blood cells
(B) White blood cells
(C) Platelets
(D) Plasma
Answer: (C)
Explanation: Platelets are cell fragments that help form clots to stop bleeding at injury sites. - Which hormone is secreted by the pancreas to lower blood sugar?
(A) Glucagon
(B) Insulin
(C) Thyroxine
(D) Adrenaline
Answer: (B)
Explanation: Insulin lowers blood sugar by promoting glucose uptake by cells. - Which plant pigment is essential for photosynthesis?
(A) Carotene
(B) Xanthophyll
(C) Chlorophyll
(D) Anthocyanin
Answer: (C)
Explanation: Chlorophyll absorbs sunlight and is crucial for converting light energy into chemical energy during photosynthesis. - Which process in plants releases oxygen as a byproduct?
(A) Respiration
(B) Photosynthesis
(C) Transpiration
(D) Fermentation
Answer: (B)
Explanation: During photosynthesis, plants use sunlight to convert carbon dioxide and water into glucose, releasing oxygen as a byproduct.