100 + Free Biology MCQs

Question 1: What is the powerhouse of the cell?

A) Mitochondria

B) Ribosome

C) Nucleus

D) Chloroplast

Explanation: Mitochondria are known as the powerhouse of the cell because they generate ATP, the cell's primary source of energy.

Question 2: What is the function of red blood cells?

A) Transport nutrients

B) Transport oxygen

C) Produce antibodies

D) Regulate body temperature

Explanation: Red blood cells (RBCs) transport oxygen from the lungs to tissues and organs across the body using hemoglobin, a protein they contain.

Question 3: What is the basic unit of life?

A) Tissue

B) Organ

C) Cell

D) Molecule

Explanation: The cell is the basic unit of life in all living organisms, as it performs essential life functions and contains the components required for survival.

Question 4: What pigment is responsible for photosynthesis in plants?

A) Carotene

B) Xanthophyll

C) Chlorophyll

D) Anthocyanin

Explanation: Chlorophyll is the green pigment in plants that captures light energy, enabling the process of photosynthesis to produce food.

Question 5: What is the main function of the ribosome?

A) Lipid synthesis

B) DNA replication

C) Protein synthesis

D) Energy production

Explanation: Ribosomes are responsible for protein synthesis by translating messenger RNA (mRNA) into amino acid chains to form proteins.

Question 6: What organelle is responsible for packaging and shipping proteins?

A) Lysosome

B) Nucleus

C) Golgi apparatus

D) Endoplasmic reticulum

Explanation: The Golgi apparatus modifies, sorts, and packages proteins for transport to various destinations within or outside the cell.

Question 7: What is the primary structural component of the cell membrane?

A) Proteins

B) Phospholipids

C) Carbohydrates

D) Cholesterol

Explanation: The cell membrane is primarily composed of a phospholipid bilayer, which provides structure and acts as a selectively permeable barrier.

Question 8: What type of cell division results in the formation of gametes?

A) Meiosis

B) Mitosis

C) Binary fission

D) Cytokinesis

Explanation: Meiosis is the type of cell division that reduces chromosome numbers by half, resulting in the formation of gametes (sperm and egg cells).

Question 9: Which macromolecule is primarily responsible for catalyzing biochemical reactions?

A) Nucleic acids

B) Lipids

C) Proteins

D) Carbohydrates

Explanation: Proteins called enzymes act as catalysts that speed up biochemical reactions without being consumed in the process.

Question 10: What is the primary function of stomata in plants?

A) Gas exchange

B) Transport nutrients

C) Store water

D) Absorb minerals

Explanation: Stomata are microscopic pores on plant leaves that facilitate the exchange of gases, such as oxygen and carbon dioxide, necessary for photosynthesis and respiration.

Question 11: Which type of RNA carries amino acids to the ribosome during protein synthesis?

A) mRNA

B) tRNA

C) rRNA

D) siRNA

Explanation: Transfer RNA (tRNA) is responsible for carrying amino acids to the ribosome, where it matches the codons in mRNA during protein synthesis.

Question 12: What process involves the conversion of glucose into ATP in the presence of oxygen?

A) Fermentation

B) Photosynthesis

C) Cellular respiration

D) Glycolysis

Explanation: Cellular respiration is the process of breaking down glucose in the presence of oxygen to produce ATP, carbon dioxide, and water.

Question 13: What is the term for organisms that produce their own food?

A) Heterotrophs

B) Autotrophs

C) Parasites

D) Decomposers

Explanation: Autotrophs are organisms capable of producing their own food, typically through photosynthesis or chemosynthesis.

Question 14: Which organ is responsible for filtering blood and producing urine?

A) Kidney

B) Liver

C) Pancreas

D) Lungs

Explanation: The kidneys filter waste products and excess substances from the blood, forming urine.

Question 15: What is the role of platelets in the blood?

A) Oxygen transport

B) Fighting infections

C) Regulating body temperature

D) Blood clotting

Explanation: Platelets play a crucial role in blood clotting by clumping together to form clots and prevent excessive bleeding.

Question 16: Which part of the plant is responsible for water absorption?

A) Roots

B) Stem

C) Leaves

D) Flowers

Explanation: Roots absorb water and minerals from the soil, which are then transported to other parts of the plant.

Question 17: What part of the brain controls balance and coordination?

A) Cerebellum

B) Cerebrum

C) Brainstem

D) Hypothalamus

Explanation: The cerebellum is responsible for maintaining balance, coordination, and fine motor skills.

Question 18: Which blood vessel carries oxygenated blood from the lungs to the heart?

A) Pulmonary vein

B) Pulmonary artery

C) Aorta

D) Vena cava

Explanation: The pulmonary vein carries oxygenated blood from the lungs to the heart for distribution to the rest of the body.

Question 19: What type of biomolecule are DNA and RNA?

A) Proteins

B) Carbohydrates

C) Nucleic acids

D) Lipids

Explanation: DNA and RNA are nucleic acids, which store and transmit genetic information in living organisms.

Question 20: What is the main site of nutrient absorption in the human body?

A) Stomach

B) Small intestine

C) Large intestine

D) Esophagus

Explanation: The small intestine is the main site for nutrient absorption due to its extensive surface area created by villi and microvilli.

Question 21: What is the term for the movement of water across a semi-permeable membrane?

A) Osmosis

B) Diffusion

C) Active transport

D) Endocytosis

Explanation: Osmosis is the movement of water molecules across a semi-permeable membrane from an area of lower solute concentration to higher solute concentration.

Question 22: What is the primary purpose of DNA replication?

A) To ensure genetic information is passed to new cells

B) To produce energy

C) To break down proteins

D) To regulate metabolism

Explanation: DNA replication ensures that every new cell receives an exact copy of the genetic information during cell division.

Question 23: Which gland in the human body regulates metabolism?

A) Thyroid gland

B) Pituitary gland

C) Adrenal gland

D) Pineal gland

Explanation: The thyroid gland regulates metabolism by releasing hormones like thyroxine (T4) and triiodothyronine (T3).

Question 24: What process do plants use to release energy stored in glucose?

A) Cellular respiration

B) Photosynthesis

C) Fermentation

D) Glycolysis

Explanation: Cellular respiration allows plants to break down glucose into ATP, which provides energy for cellular activities.

Question 25: What is the name of the protein that carries oxygen in red blood cells?

A) Myoglobin

B) Hemoglobin

C) Collagen

D) Keratin

Explanation: Hemoglobin is the protein in red blood cells that binds to oxygen and transports it throughout the body.

Question 26: What type of bond holds the two DNA strands together?

A) Hydrogen bond

B) Covalent bond

C) Ionic bond

D) Peptide bond

Explanation: Hydrogen bonds between the nitrogenous bases of the DNA strands hold them together, ensuring a stable double-helix structure.

Question 27: Which organelle contains digestive enzymes to break down waste?

A) Lysosome

B) Mitochondria

C) Golgi apparatus

D) Endoplasmic reticulum

Explanation: Lysosomes contain enzymes that digest cellular waste, such as damaged organelles and macromolecules.

Question 28: What is the primary function of white blood cells?

A) Transport nutrients

B) Maintain blood pressure

C) Fight infections

D) Oxygen transport

Explanation: White blood cells are a key component of the immune system, protecting the body from infections and foreign invaders.

Question 29: What is the role of chloroplasts in plant cells?

A) Photosynthesis

B) Cellular respiration

C) Protein synthesis

D) Storage of genetic information

Explanation: Chloroplasts contain chlorophyll and are responsible for photosynthesis, the process by which plants convert sunlight into energy.

Question 30: What is the universal solvent in biological systems?

A) Water

B) Ethanol

C) Acetone

D) Glycine

Explanation: Water is known as the universal solvent because it can dissolve various substances, making it essential for biological processes.

Question 31: What is the term for the programmed cell death that helps in organism development?

A) Autolysis

B) Apoptosis

C) Necrosis

D) Cytolysis

Explanation: Apoptosis is a controlled process of programmed cell death that plays an essential role in development, growth, and maintaining tissue health.

Question 32: Which part of the cell synthesizes lipids?

A) Nucleus

B) Lysosome

C) Smooth endoplasmic reticulum

D) Mitochondria

Explanation: The smooth endoplasmic reticulum is the site of lipid synthesis, including fats and steroid hormones, in eukaryotic cells.

Question 33: What term describes the genetic makeup of an organism?

A) Phenotype

B) Genotype

C) Karyotype

D) Genome

Explanation: Genotype refers to the genetic makeup or set of genes that an organism carries, determining its characteristics.

Question 34: What is the primary function of xylem in plants?

A) Transport glucose

B) Transport water

C) Transport oxygen

D) Transport nitrogen

Explanation: Xylem tissue is responsible for transporting water and nutrients from the roots to other parts of the plant.

Question 35: Which molecule is known as the energy currency of the cell?

A) NADH

B) FADH2

C) ATP

D) ADP

Explanation: ATP (adenosine triphosphate) is called the energy currency of the cell because it stores and provides energy for cellular functions.

Question 36: What is the function of the ribosome in a cell?

A) Stores genetic material

B) Synthesizes proteins

C) Breaks down waste

D) Generates energy

Explanation: Ribosomes are responsible for synthesizing proteins by translating messenger RNA (mRNA) sequences into amino acid chains.

Question 37: Which process converts light energy into chemical energy in plants?

A) Cellular respiration

B) Photosynthesis

C) Fermentation

D) Glycolysis

Explanation: Photosynthesis is the process in which plants use sunlight, carbon dioxide, and water to create glucose and oxygen.

Question 38: What is the largest internal organ in the human body?

A) Liver

B) Kidney

C) Heart

D) Lungs

Explanation: The liver is the largest internal organ and performs various vital functions, including detoxification and production of bile.

Question 39: What type of macromolecule is an enzyme?

A) Lipid

B) Protein

C) Carbohydrate

D) Nucleic acid

Explanation: Enzymes are a type of protein that act as biological catalysts, speeding up chemical reactions in the body.

Question 40: What cells are responsible for carrying oxygen in the blood?

A) Red blood cells

B) White blood cells

C) Platelets

D) Plasma cells

Explanation: Red blood cells, or erythrocytes, contain hemoglobin, a protein that binds to oxygen and transports it throughout the body.

Question 41: Which organ system is responsible for hormone production?

A) Nervous system

B) Muscular system

C) Endocrine system

D) Circulatory system

Explanation: The endocrine system consists of glands that produce hormones, which regulate various body functions like metabolism and growth.

Question 42: What is the purpose of the large intestine in the digestive system?

A) Absorbs most nutrients

B) Absorbs water and compact waste

C) Produces digestive enzymes

D) Metabolizes proteins

Explanation: The large intestine absorbs water and electrolytes from waste material, forming and compacting stool for excretion.

Question 43: Which gas is the primary product of cellular respiration?

A) Oxygen

B) Carbon dioxide

C) Nitrogen

D) Methane

Explanation: Carbon dioxide is the primary byproduct of cellular respiration when glucose is broken down to produce energy (ATP).

Question 44: What is the term for organisms that consume other organisms for energy?

A) Autotrophs

B) Heterotrophs

C) Decomposers

D) Producers

Explanation: Heterotrophs are organisms that obtain energy by feeding on other organisms, unlike autotrophs that produce their own food.

Question 45: What pigment is primarily responsible for the green color of plants?

A) Chlorophyll

B) Carotene

C) Xanthophyll

D) Hemoglobin

Explanation: Chlorophyll is the green pigment in plants that captures light energy for use in photosynthesis.

Question 46: Which organ in the human body filters waste from the blood to form urine?

A) Liver

B) Lungs

C) Kidneys

D) Pancreas

Explanation: The kidneys filter blood to remove waste and excess fluids, forming urine for excretion.

Question 47: What is the term for the basic functional unit of the nervous system?

A) Neuron

B) Synapse

C) Axon

D) Dendrite

Explanation: A neuron is the basic unit of the nervous system responsible for transmitting signals throughout the body.

Question 48: What structure in a cell controls the entry and exit of substances?

A) Cell membrane

B) Nucleus

C) Cytoplasm

D) Mitochondria

Explanation: The cell membrane acts as a selective barrier, allowing some substances to pass while keeping others out.

Question 49: What is the primary function of the immune system?

A) Digest food

B) Circulate blood

C) Produce energy

D) Protect against disease

Explanation: The immune system defends the body against pathogens like bacteria and viruses, maintaining overall health.

Question 50: What is the primary function of red bone marrow?

A) Store calcium

B) Produce blood cells

C) Store fat

D) Filter blood

Explanation: Red bone marrow produces red blood cells, white blood cells, and platelets, essential for oxygen transport and immunity.

Question 51: Which blood group is considered the universal donor?

A) O negative

B) AB positive

C) A positive

D) B negative

Explanation: O negative blood can be safely given to individuals of any blood type, making it the universal donor type.

Question 52: What is the structural and functional unit of the kidney?

A) Nephron

B) Glomerulus

C) Renal cortex

D) Collecting duct

Explanation: The nephron is the fundamental unit of the kidney, responsible for filtering blood and forming urine.

Question 53: What process allows plants to lose water through small openings on their leaves?

A) Transpiration

B) Photosynthesis

C) Respiration

D) Germination

Explanation: Transpiration is the process by which water evaporates through stomata, cooling the plant and aiding nutrient transport.

Question 54: What is the term for organisms that can produce their own food using sunlight?

A) Heterotrophs

B) Autotrophs

C) Decomposers

D) Parasites

Explanation: Autotrophs, such as plants, produce their own energy-rich food through processes like photosynthesis.

Question 55: Which type of tissue is responsible for transporting food in plants?

A) Xylem

B) Phloem

C) Cambium

D) Epidermis

Explanation: Phloem transports sugars and other organic nutrients from the leaves to other parts of the plant.

Question 56: What is the function of mitochondria in a cell?

A) Protein synthesis

B) Store genetic material

C) Produce energy

D) Transport nutrients

Explanation: Mitochondria are known as the powerhouse of the cell, producing energy in the form of ATP by cellular respiration.

Question 57: Which part of the flower develops into a fruit?

A) Petal

B) Ovary

C) Stigma

D) Anther

Explanation: The ovary of a flower matures into a fruit after fertilization, enclosing the seeds within.

Question 58: What is the role of hemoglobin in the blood?

A) Transport oxygen

B) Digest food

C) Maintain blood pressure

D) Regulate temperature

Explanation: Hemoglobin in red blood cells binds to oxygen and carries it from the lungs to tissues throughout the body.

Question 59: What is the basic building block of proteins?

A) Amino acids

B) Fatty acids

C) Glucose

D) Nucleotides

Explanation: Proteins are made up of chains of amino acids, which are joined together by peptide bonds.

Question 60: Which part of the brain is responsible for balance and coordination?

A) Cerebrum

B) Cerebellum

C) Medulla oblongata

D) Hypothalamus

Explanation: The cerebellum controls muscle coordination and balance, ensuring smooth movement of the body.

Question 61: What is the main function of stomata in plants?

A) Gas exchange

B) Absorption of nutrients

C) Structural support

D) Photosynthesis

Explanation: Stomata are small openings on leaves that allow for the exchange of gases like carbon dioxide and oxygen between the plant and its environment.

Question 62: What type of cell division results in two identical daughter cells?

A) Mitosis

B) Meiosis

C) Binary fission

D) Cytokinesis

Explanation: Mitosis is a type of cell division that produces two genetically identical daughter cells, critical for growth and repair.

Question 63: Which molecule carries genetic instructions?

A) RNA

B) DNA

C) Protein

D) Lipid

Explanation: DNA (deoxyribonucleic acid) stores genetic information that guides the development, function, and reproduction of organisms.

Question 64: What is the primary function of the small intestine?

A) Produce enzymes

B) Absorb nutrients

C) Filter toxins

D) Store waste

Explanation: The small intestine is the site of nutrient absorption, where digested food is transferred to the bloodstream for use by the body.

Question 65: What is the term for the process by which cells release energy from glucose?

A) Cellular respiration

B) Photosynthesis

C) Fermentation

D) Glycolysis

Explanation: Cellular respiration is the process by which cells break down glucose and produce ATP, providing energy for cellular activities.

Question 66: What is the main function of white blood cells?

A) Fight infections

B) Carry oxygen

C) Transport hormones

D) Store nutrients

Explanation: White blood cells are an essential part of the immune system, protecting the body from infections and foreign invaders.

Question 67: Which organelle is known as the control center of the cell?

A) Nucleus

B) Mitochondria

C) Ribosome

D) Lysosome

Explanation: The nucleus controls cell activities by managing gene expression and storing the cell's genetic material, DNA.

Question 68: What does biodiversity refer to?

A) Number of people in an area

B) Variety of climates

C) Variety of life forms

D) Types of soil

Explanation: Biodiversity refers to the variety of life on Earth, including species, ecosystems, and genetic diversity, which supports ecological health.

Question 69: Which molecule is the primary energy carrier in cells?

A) DNA

B) ATP

C) Lipids

D) Proteins

Explanation: ATP (Adenosine Triphosphate) is the primary energy carrier in cells, powering biochemical reactions.

Question 70: What is the process of producing gametes in humans called?

A) Mitosis

B) Meiosis

C) Fertilization

D) Differentiation

Explanation: Meiosis is a type of cell division that reduces the chromosome number by half, resulting in the formation of gametes (sperm and eggs).

Question 71: Which nutrient is primarily responsible for muscle growth and repair?

A) Protein

B) Carbohydrate

C) Fat

D) Vitamins

Explanation: Proteins are made up of amino acids, which are necessary for muscle tissue repair and growth.

Question 72: What is the main role of chloroplasts in plant cells?

A) Photosynthesis

B) Cellular respiration

C) Protein synthesis

D) Water storage

Explanation: Chloroplasts contain chlorophyll and are the site of photosynthesis, where light energy is converted into chemical energy in plants.

Question 73: Which type of RNA carries the genetic code from DNA to the ribosome?

A) mRNA

B) tRNA

C) rRNA

D) sRNA

Explanation: Messenger RNA (mRNA) carries genetic information from DNA to the ribosome for protein synthesis.

Question 74: What is the name of the process by which water moves across a selectively permeable membrane?

A) Osmosis

B) Diffusion

C) Active transport

D) Endocytosis

Explanation: Osmosis is the movement of water molecules across a selectively permeable membrane from a region of lower solute concentration to higher solute concentration.

Question 75: Which organisms are responsible for converting nitrogen in the air into a form plants can use?

A) Fungi

B) Nitrogen-fixing bacteria

C) Algae

D) Protozoa

Explanation: Nitrogen-fixing bacteria, such as Rhizobium, convert atmospheric nitrogen into ammonia, a form usable by plants for growth.

Question 76: What is the primary function of platelets in the blood?

A) Blood clotting

B) Fighting infections

C) Carrying oxygen

D) Regulating temperature

Explanation: Platelets, or thrombocytes, are small cell fragments that play a vital role in blood clotting and preventing excessive bleeding.

Question 77: Which gas is most abundant in Earth's atmosphere?

A) Nitrogen

B) Oxygen

C) Carbon dioxide

D) Argon

Explanation: Nitrogen makes up around 78% of Earth's atmosphere, making it the most abundant gas.

Question 78: What is the process by which green plants make their own food?

A) Respiration

B) Photosynthesis

C) Fermentation

D) Transpiration

Explanation: Photosynthesis is the process where plants use sunlight, carbon dioxide, and water to produce glucose and oxygen.

Question 79: What is the primary function of the large intestine in digestion?

A) Absorb water

B) Break down protein

C) Store bile

D) Digest fats

Explanation: The large intestine absorbs water from undigested food and forms solid waste for excretion.

Question 80: What type of respiration occurs without oxygen?

A) Aerobic

B) Anaerobic

C) Cellular

D) Oxidative

Explanation: Anaerobic respiration takes place without oxygen, producing energy by breaking down glucose through processes like fermentation.

Question 81: What is the role of the endocrine system?

A) Circulate blood

B) Regulate hormones

C) Protect from infection

D) Provide structural support

Explanation: The endocrine system produces hormones that regulate bodily functions like growth, metabolism, and reproduction.

Question 82: What is the smallest unit of life?

A) Cell

B) Atom

C) Tissue

D) Organ

Explanation: The cell is the basic structural and functional unit of life, capable of performing all life processes.

Question 83: Which organ is responsible for detoxifying chemicals in the human body?

A) Liver

B) Kidney

C) Lungs

D) Spleen

Explanation: The liver processes and detoxifies chemicals in the blood, removing toxins and aiding in metabolism.

Question 84: What is the primary function of the ribosome?

A) Protein synthesis

B) Energy production

C) DNA replication

D) Transport molecules

Explanation: Ribosomes are responsible for synthesizing proteins by assembling amino acids in the order specified by mRNA.

Question 85: Which part of the plant anchors it to the ground and absorbs water and nutrients?

A) Roots

B) Stem

C) Leaves

D) Flowers

Explanation: Roots anchor the plant in the soil and absorb water and nutrients necessary for growth.

Question 86: What is the structural and functional unit of the kidney?

A) Nephron

B) Alveoli

C) Villus

D) Axon

Explanation: The nephron is the basic unit of the kidney responsible for filtering blood and forming urine.

Question 87: Which type of blood vessel carries blood away from the heart?

A) Artery

B) Vein

C) Capillary

D) Aorta

Explanation: Arteries carry oxygenated blood away from the heart to the rest of the body, except for the pulmonary artery, which carries deoxygenated blood to the lungs.

Question 88: What is the name of the pigment that gives skin its color?

A) Keratin

B) Melanin

C) Hemoglobin

D) Chlorophyll

Explanation: Melanin is the pigment that determines skin color and protects it from UV radiation.

Question 89: Which part of the cell contains the genetic material?

A) Nucleus

B) Cytoplasm

C) Ribosome

D) Mitochondria

Explanation: The nucleus contains DNA, the genetic material that controls cell functions and inheritance.

Question 90: What is the term for animals that maintain a constant body temperature?

A) Warm-blooded

B) Cold-blooded

C) Amphibians

D) Herbivores

Explanation: Warm-blooded animals, like mammals and birds, maintain a stable internal temperature regardless of the environment.

Question 91: Which process is responsible for variation in sexually reproducing organisms?

A) Mitosis

B) Meiosis

C) Binary fission

D) Osmosis

Explanation: Meiosis creates genetic variation by shuffling genes during gamete formation, ensuring unique offspring.

Question 92: What is the role of the xylem in plants?

A) Transport water

B) Transport sugars

C) Perform photosynthesis

D) Store nutrients

Explanation: Xylem transports water and minerals from the roots to the leaves of the plant.

Question 93: Which part of the neuron receives incoming signals?

A) Dendrites

B) Axon

C) Cell body

D) Synapse

Explanation: Dendrites are branch-like structures that receive electrical signals and transmit them to the neuron’s cell body.

Question 94: What is the thick-walled vessel that carries blood from the heart to the lungs?

A) Pulmonary artery

B) Pulmonary vein

C) Aorta

D) Vena cava

Explanation: The pulmonary artery carries deoxygenated blood from the heart to the lungs for oxygenation.

Question 95: What is the green pigment in plants that absorbs sunlight?

A) Chlorophyll

B) Carotenoids

C) Anthocyanin

D) Flavonoids

Explanation: Chlorophyll absorbs light energy for photosynthesis, giving plants their green color.

Question 96: What is the primary organ involved in the process of photosynthesis?

A) Roots

B) Stem

C) Leaves

D) Flowers

Explanation: Leaves contain chloroplasts, which are essential for photosynthesis by absorbing sunlight and producing energy for the plant.

Question 97: What is the name of the process by which cells divide to create two identical cells?

A) Mitosis

B) Meiosis

C) Binary fission

D) Cytokinesis

Explanation: Mitosis is the process where one cell divides into two identical daughter cells, maintaining the same chromosome number.

Question 98: Which biomolecule is the main source of energy for cells?

A) Carbohydrates

B) Lipids

C) Proteins

D) Nucleic acids

Explanation: Carbohydrates, such as glucose, are broken down during cellular respiration to provide energy in the form of ATP.

Question 99: What type of joint is found in the human shoulder?

A) Ball-and-socket joint

B) Hinge joint

C) Pivot joint

D) Saddle joint

Explanation: The ball-and-socket joint allows for a wide range of motion, making it ideal for the shoulder's mobility.

Question 100: What is the term for a species that can no longer be found in the wild?

A) Endangered

B) Extinct

C) Vulnerable

D) Threatened

Explanation: A species is classified as extinct when no individuals remain alive in the wild or captivity.

Question 101: Which part of the brain controls balance and coordination?

A) Medulla

B) Cerebellum

C) Cerebrum

D) Hypothalamus

Explanation: The cerebellum is responsible for maintaining balance, posture, and coordinating voluntary movements.

Question 102: What is the main function of red blood cells?

A) Transport oxygen

B) Fight infections

C) Clot blood

D) Digest food

Explanation: Red blood cells contain hemoglobin, which binds to oxygen and transports it to tissues throughout the body.

Question 103: What is the function of stomata in plants?

A) Gas exchange

B) Absorb nutrients

C) Transport water

D) Store glucose

Explanation: Stomata are small openings on the leaf surface that regulate gas exchange, including oxygen, carbon dioxide, and water vapor.

Question 104: What is the name for the protein that speeds up chemical reactions in the body?

A) Enzyme

B) Hormone

C) Antibody

D) Hemoglobin

Explanation: Enzymes are biological catalysts that accelerate chemical reactions without being consumed in the process.

Question 105: What is the liquid part of blood called?

A) Plasma

B) Platelets

C) Hemoglobin

D) Serum

Explanation: Plasma is the liquid part of blood that carries cells, nutrients, hormones, and waste throughout the body.

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