- Which process is responsible for the exchange of oxygen and carbon dioxide in the lungs?
A) Filtration
B) Diffusion
C) Active transport
D) Osmosis
Correct Answer: B) Diffusion
Explanation: Diffusion allows oxygen to move from the alveoli (high concentration) into the blood (low concentration) and carbon dioxide to move in the opposite direction, enabling efficient gas exchange during breathing. - Which blood group is considered the universal donor?
A) A
B) B
C) AB
D) O
Correct Answer: D) O
Explanation: Blood group O negative lacks A, B, and Rh antigens, so it can be donated to any other group without causing an immune reaction, making it the universal donor. - Which part of the brain is responsible for regulating hunger and thirst?
A) Cerebellum
B) Medulla oblongata
C) Hypothalamus
D) Cerebrum
Correct Answer: C) Hypothalamus
Explanation: The hypothalamus controls homeostatic functions, including hunger, thirst, body temperature, and hormone release, by responding to internal signals. - Which mineral is essential for the formation of strong teeth and bones?
A) Sodium
B) Calcium
C) Iron
D) Zinc
Correct Answer: B) Calcium
Explanation: Calcium is a major component of bones and teeth, providing strength and structure. Its deficiency can lead to weak bones and dental problems. - Which process describes the breakdown of food into simpler substances?
A) Digestion
B) Absorption
C) Assimilation
D) Egestion
Correct Answer: A) Digestion
Explanation: Digestion involves mechanical and chemical processes that break down complex food molecules into simpler forms that can be absorbed by the body. - Which structure in plant cells is responsible for photosynthesis?
A) Mitochondria
B) Chloroplast
C) Ribosome
D) Nucleus
Correct Answer: B) Chloroplast
Explanation: Chloroplasts contain chlorophyll, which captures sunlight and converts it into chemical energy during photosynthesis. - Which hormone regulates the level of calcium in the blood?
A) Insulin
B) Parathyroid hormone
C) Glucagon
D) Adrenaline
Correct Answer: B) Parathyroid hormone
Explanation: Parathyroid hormone increases blood calcium levels by stimulating bone resorption, increasing calcium absorption in the intestine, and reducing calcium loss in urine. - Which process enables water to move from the roots to the leaves of a plant?
A) Transpiration
B) Respiration
C) Translocation
D) Photosynthesis
Correct Answer: A) Transpiration
Explanation: Transpiration creates a pull that draws water upward from the roots through the xylem to the leaves, where it evaporates. - Which vitamin is essential for blood clotting?
A) Vitamin A
B) Vitamin C
C) Vitamin K
D) Vitamin D
Correct Answer: C) Vitamin K
Explanation: Vitamin K is required for the synthesis of proteins involved in blood clotting, preventing excessive bleeding. - Which organ is responsible for detoxifying harmful substances in the blood?
A) Kidney
B) Liver
C) Pancreas
D) Spleen
Correct Answer: B) Liver
Explanation: The liver metabolizes and detoxifies drugs, alcohol, and other harmful substances, converting them into less toxic forms for excretion. - Which structure in the human eye is responsible for detecting light?
A) Iris
B) Lens
C) Retina
D) Cornea
Correct Answer: C) Retina
Explanation: The retina contains photoreceptor cells (rods and cones) that detect light and convert it into electrical signals sent to the brain. - Which process describes the movement of molecules from an area of high concentration to low concentration?
A) Active transport
B) Diffusion
C) Endocytosis
D) Exocytosis
Correct Answer: B) Diffusion
Explanation: Diffusion is the passive movement of molecules down their concentration gradient, requiring no energy. - Which part of the flower produces ovules?
A) Stamen
B) Anther
C) Ovary
D) Petal
Correct Answer: C) Ovary
Explanation: The ovary, part of the pistil, contains ovules, which develop into seeds after fertilization. - Which enzyme breaks down fats in the digestive system?
A) Amylase
B) Lipase
C) Pepsin
D) Maltase
Correct Answer: B) Lipase
Explanation: Lipase is produced by the pancreas and breaks down dietary fats into fatty acids and glycerol in the small intestine. - Which part of the neuron carries impulses away from the cell body?
A) Dendrite
B) Axon
C) Synapse
D) Nucleus
Correct Answer: B) Axon
Explanation: The axon is a long projection that transmits nerve impulses away from the neuron’s cell body toward other neurons or effectors. - Which organ in the human body produces bile?
A) Pancreas
B) Liver
C) Gallbladder
D) Stomach
Correct Answer: B) Liver
Explanation: The liver produces bile, which is stored in the gallbladder and released into the small intestine to aid in fat digestion. - Which disease is caused by a deficiency of vitamin B12?
A) Scurvy
B) Rickets
C) Pernicious anemia
D) Night blindness
Correct Answer: C) Pernicious anemia
Explanation: Vitamin B12 deficiency leads to pernicious anemia, characterized by large, immature red blood cells and neurological symptoms. - Which structure in the heart receives oxygenated blood from the lungs?
A) Right atrium
B) Right ventricle
C) Left atrium
D) Left ventricle
Correct Answer: C) Left atrium
Explanation: The left atrium receives oxygen-rich blood from the lungs via the pulmonary veins before passing it to the left ventricle. - Which hormone is responsible for the “fight or flight” response?
A) Insulin
B) Adrenaline
C) Thyroxine
D) Progesterone
Correct Answer: B) Adrenaline
Explanation: Adrenaline, secreted by the adrenal medulla, prepares the body to respond to stress by increasing heart rate, blood pressure, and energy availability. - Which process allows plants to reproduce without seeds?
A) Sexual reproduction
B) Vegetative propagation
C) Pollination
D) Germination
Correct Answer: B) Vegetative propagation
Explanation: Vegetative propagation is a form of asexual reproduction where new plants grow from parts such as stems, roots, or leaves, without the need for seeds. - Which part of the human skeleton protects the heart and lungs?
A) Skull
B) Rib cage
C) Pelvis
D) Vertebral column
Correct Answer: B) Rib cage
Explanation: The rib cage is a bony structure that surrounds and protects the heart and lungs from injury. - Which hormone stimulates milk production in mammals?
A) Oxytocin
B) Prolactin
C) Estrogen
D) Progesterone
Correct Answer: B) Prolactin
Explanation: Prolactin, produced by the pituitary gland, stimulates the mammary glands to produce milk after childbirth. - Which process describes the conversion of atmospheric nitrogen into ammonia by bacteria?
A) Nitrification
B) Denitrification
C) Nitrogen fixation
D) Ammonification
Correct Answer: C) Nitrogen fixation
Explanation: Nitrogen fixation is carried out by certain bacteria and converts inert atmospheric nitrogen into ammonia, which plants can use. - Which part of the human ear is responsible for maintaining balance?
A) Cochlea
B) Semicircular canals
C) Ossicles
D) Eardrum
Correct Answer: B) Semicircular canals
Explanation: The semicircular canals in the inner ear detect head movements and help maintain the body’s sense of balance. - Which mineral is necessary for the synthesis of thyroid hormones?
A) Calcium
B) Iron
C) Iodine
D) Magnesium
Correct Answer: C) Iodine
Explanation: Iodine is an essential component of thyroid hormones, which regulate metabolism. Its deficiency can cause goiter. - Which type of blood vessel has the thickest walls?
A) Vein
B) Artery
C) Capillary
D) Venule
Correct Answer: B) Artery
Explanation: Arteries have thick, muscular walls to withstand the high pressure of blood pumped from the heart. - Which vitamin is essential for healthy skin and vision?
A) Vitamin A
B) Vitamin C
C) Vitamin D
D) Vitamin K
Correct Answer: A) Vitamin A
Explanation: Vitamin A is necessary for the maintenance of healthy skin, vision, and immune function. - Which process occurs in the mitochondria of cells?
A) Photosynthesis
B) Aerobic respiration
C) Protein synthesis
D) DNA replication
Correct Answer: B) Aerobic respiration
Explanation: Mitochondria are the site of aerobic respiration, where glucose is broken down in the presence of oxygen to produce ATP. - Which gland is known as the “master gland” of the endocrine system?
A) Thyroid
B) Pituitary
C) Adrenal
D) Pancreas
Correct Answer: B) Pituitary
Explanation: The pituitary gland controls the activity of other endocrine glands by secreting various hormones. - Which disease is caused by a deficiency of vitamin D in children?
A) Rickets
B) Scurvy
C) Beriberi
D) Pellagra
Correct Answer: A) Rickets
Explanation: Rickets is a bone disorder in children caused by vitamin D deficiency, resulting in soft, weak bones. - Which part of the plant is responsible for producing seeds?
A) Root
B) Stem
C) Flower
D) Leaf
Correct Answer: C) Flower
Explanation: Flowers contain reproductive organs that produce seeds after fertilization. - Which organ in the human body is responsible for producing insulin?
A) Liver
B) Pancreas
C) Kidney
D) Spleen
Correct Answer: B) Pancreas
Explanation: The pancreas contains beta cells that produce insulin, a hormone that lowers blood glucose levels. - Which process describes the movement of water molecules from high to low concentration through a membrane?
A) Active transport
B) Osmosis
C) Diffusion
D) Endocytosis
Correct Answer: B) Osmosis
Explanation: Osmosis is the passive movement of water molecules through a semi-permeable membrane from an area of high water concentration to low water concentration. - Which hormone is responsible for the development of secondary sexual characteristics in females?
A) Testosterone
B) Estrogen
C) Progesterone
D) Insulin
Correct Answer: B) Estrogen
Explanation: Estrogen, produced by the ovaries, promotes the development of female secondary sexual characteristics such as breast development and wider hips. - Which organ filters blood to remove waste and excess water, forming urine?
A) Liver
B) Kidney
C) Spleen
D) Pancreas
Correct Answer: B) Kidney
Explanation: The kidneys filter waste products and excess water from the blood, producing urine for excretion. - Which part of the human respiratory system prevents food from entering the windpipe?
A) Larynx
B) Epiglottis
C) Trachea
D) Bronchi
Correct Answer: B) Epiglottis
Explanation: The epiglottis is a flap of tissue that closes over the trachea during swallowing, preventing food from entering the airway. - Which vitamin deficiency causes scurvy?
A) Vitamin A
B) Vitamin B12
C) Vitamin C
D) Vitamin D
Correct Answer: C) Vitamin C
Explanation: Scurvy is caused by a deficiency of vitamin C, leading to bleeding gums, weakness, and poor wound healing. - Which process produces gametes in animals?
A) Mitosis
B) Meiosis
C) Binary fission
D) Budding
Correct Answer: B) Meiosis
Explanation: Meiosis is a type of cell division that produces gametes (sperm and eggs) with half the normal chromosome number. - Which hormone stimulates the release of glucose from the liver into the blood?
A) Insulin
B) Glucagon
C) Thyroxine
D) Cortisol
Correct Answer: B) Glucagon
Explanation: Glucagon, produced by the pancreas, signals the liver to convert stored glycogen into glucose and release it into the blood. - Which part of the human skeleton protects the brain?
A) Rib cage
B) Pelvis
C) Skull
D) Vertebral column
Correct Answer: C) Skull
Explanation: The skull is a bony structure that encases and protects the brain from injury. - Which enzyme breaks down proteins in the stomach?
A) Amylase
B) Lipase
C) Pepsin
D) Maltase
Correct Answer: C) Pepsin
Explanation: Pepsin is a protease enzyme secreted by the stomach that digests proteins into smaller peptides. - Which structure in the plant cell stores water, nutrients, and waste products?
A) Mitochondria
B) Chloroplast
C) Vacuole
D) Ribosome
Correct Answer: C) Vacuole
Explanation: The vacuole is a large, membrane-bound organelle in plant cells that stores water, nutrients, and waste products, helping maintain cell turgor. - Which process describes the transfer of pollen from anther to stigma?
A) Fertilization
B) Germination
C) Pollination
D) Seed dispersal
Correct Answer: C) Pollination
Explanation: Pollination is the transfer of pollen from the male anther to the female stigma, enabling fertilization in plants. - Which mineral is essential for the production of hemoglobin?
A) Calcium
B) Iron
C) Potassium
D) Sodium
Correct Answer: B) Iron
Explanation: Iron is a key component of hemoglobin, the protein in red blood cells that carries oxygen. - Which organ in the human body stores bile?
A) Liver
B) Pancreas
C) Gallbladder
D) Stomach
Correct Answer: C) Gallbladder
Explanation: The gallbladder stores and concentrates bile produced by the liver, releasing it into the small intestine to aid in fat digestion. - Which process describes the breakdown of glucose to release energy in the absence of oxygen?
A) Aerobic respiration
B) Anaerobic respiration
C) Photosynthesis
D) Chemosynthesis
Correct Answer: B) Anaerobic respiration
Explanation: Anaerobic respiration (fermentation) breaks down glucose without oxygen, producing less energy and byproducts like lactic acid or ethanol. - Which part of the human blood is responsible for clotting?
A) Red blood cells
B) White blood cells
C) Platelets
D) Plasma
Correct Answer: C) Platelets
Explanation: Platelets are cell fragments that help form clots to stop bleeding at injury sites. - Which hormone regulates the sleep-wake cycle?
A) Melatonin
B) Insulin
C) Adrenaline
D) Thyroxine
Correct Answer: A) Melatonin
Explanation: Melatonin, produced by the pineal gland, regulates circadian rhythms and the sleep-wake cycle. - Which process describes the movement of food through the digestive tract by muscular contractions?
A) Peristalsis
B) Digestion
C) Absorption
D) Assimilation
Correct Answer: A) Peristalsis
Explanation: Peristalsis is the wave-like contraction of smooth muscles that moves food along the digestive tract. - Which organ in the human body is responsible for producing urea?
A) Kidney
B) Liver
C) Pancreas
D) Spleen
Correct Answer: B) Liver
Explanation: The liver converts toxic ammonia, a byproduct of protein metabolism, into urea, which is then excreted by the kidneys in urine.