41. What is pollination?
a) Formation of seeds
b) Transfer of pollen from anther to stigma
c) Fertilization of eggs by sperm
d) Growth of a seed into a plant
Answer: b) Transfer of pollen from anther to stigma
Explanation: Pollination allows fertilization by transferring pollen to the female reproductive parts.
42. Which plant structure protects seeds?
a) Flower
b) Fruit
c) Root
d) Leaf
Answer: b) Fruit
Explanation: Fruits develop from the ovary and protect seeds.
13. Nutrition in Animals and Plants
43. Which enzyme in saliva breaks down starch into sugars?
a) Pepsin
b) Amylase
c) Lipase
d) Trypsin
Answer: b) Amylase
Explanation: Amylase, present in saliva, initiates the digestion of starch into maltose.
44. What is the primary function of bile in digestion?
a) Break down proteins
b) Neutralize stomach acid and emulsify fats
c) Digest carbohydrates
d) Absorb nutrients
Answer: b) Neutralize stomach acid and emulsify fats
Explanation: Bile, produced by the liver, breaks large fat globules into smaller ones for easier digestion.
45. Which part of the digestive system is responsible for nutrient absorption?
a) Stomach
b) Small intestine
c) Large intestine
d) Esophagus
Answer: b) Small intestine
Explanation: The small intestine has villi that increase surface area for nutrient absorption.
46. In plants, which pigment captures sunlight for photosynthesis?
a) Chlorophyll
b) Carotene
c) Anthocyanin
d) Xanthophyll
Answer: a) Chlorophyll
Explanation: Chlorophyll absorbs light energy, essential for photosynthesis.
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14. Ecosystem
47. What is the role of producers in an ecosystem?
a) Consume other organisms
b) Convert solar energy into chemical energy
c) Break down dead matter
d) Recycle nutrients
Answer: b) Convert solar energy into chemical energy
Explanation: Producers like plants perform photosynthesis to make food.
48. What happens to the population of secondary consumers if the primary consumers decrease?
a) Increases
b) Remains stable
c) Decreases
d) Becomes extinct
Answer: c) Decreases
Explanation: Secondary consumers depend on primary consumers for food, so their population decreases when primary consumers decline.
49. Which process removes carbon dioxide from the atmosphere?
a) Respiration
b) Combustion
c) Photosynthesis
d) Decomposition
Answer: c) Photosynthesis
Explanation: Photosynthesis uses carbon dioxide to produce glucose, reducing CO₂ levels.
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15. Reaching the Age of Adolescence
50. Which gland secretes growth hormone?
a) Thyroid
b) Pituitary
c) Adrenal
d) Pancreas
Answer: b) Pituitary
Explanation: The pituitary gland is the master gland and secretes growth hormone.
51. What causes voice change in boys during puberty?
a) Growth hormone
b) Estrogen
c) Testosterone
d) Thyroxine
Answer: c) Testosterone
Explanation: Testosterone leads to the growth of the larynx and deepening of the voice.
52. What is the term for the onset of reproductive ability in humans?
a) Adolescence
b) Puberty
c) Fertilization
d) Menopause
Answer: b) Puberty
Explanation: Puberty marks the beginning of sexual maturity and the ability to reproduce.
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16. Genetics and DNA
53. What is the basic unit of heredity?
a) DNA
b) Gene
c) Chromosome
d) Protein
Answer: b) Gene
Explanation: Genes are segments of DNA that carry genetic information.
54. What is the shape of a DNA molecule?
a) Circular
b) Linear
c) Double helix
d) Single strand
Answer: c) Double helix
Explanation: DNA has a double-helix structure formed by two strands.
55. Which of the following pairs is correctly matched?
a) Adenine – Cytosine
b) Thymine – Adenine
c) Guanine – Thymine
d) Cytosine – Thymine
Answer: b) Thymine – Adenine
Explanation: In DNA, adenine pairs with thymine, and cytosine pairs with guanine.
17. Evolution and Adaptation
56. What is “speciation”?
a) Extinction of species
b) Formation of new species
c) Migration of species
d) Domestication of species
Answer: b) Formation of new species
Explanation: Speciation occurs when populations evolve to become distinct species.
57. Which process drives natural selection?
a) Random mutations
b) Survival of the fittest
c) Artificial breeding
d) Deforestation
Answer: b) Survival of the fittest
Explanation: Organisms with advantageous traits are more likely to survive and reproduce.
58. What is the term for the remains of ancient organisms?
a) Fossils
b) Genes
c) Enzymes
d) Chromosomes
Answer: a) Fossils
Explanation: Fossils are preserved remains or traces of organisms from the past.
18. Human Circulatory System
59. What prevents the backflow of blood in the heart?
a) Arteries
b) Valves
c) Veins
d) Atria
Answer: b) Valves
Explanation: Valves in the heart ensure that blood flows in the correct direction.
60. Which blood group is known as the universal donor?
a) A
b) B
c) AB
d) O
Answer: d) O
Explanation: Blood group O can be donated to all other blood groups.
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