81. Which part of the eye controls the amount of light entering?
✅ A. Iris
a: Iris | b: Optic nerve | c: Retina | d: Cornea only Read more
Biology MCQs – Page 5
82. Which structure controls what enters and leaves a cell?
✅ A. Cell membrane
a: Cell membrane | b: Nucleolus | c: Chromosome | d: Cell wall only Read more
83. What is the largest organ of the human body?
✅ A. Skin
a: Skin | b: Brain | c: Lung | d: Liver Read more
84. Which molecule is the main immediate energy currency of cells?
✅ B. ATP
a: DNA | b: ATP | c: Starch | d: RNA Read more
85. Which organisms make their own food using sunlight in most ecosystems?
✅ D. Producers
a: Decomposers only | b: Predators | c: Primary consumers | d: Producers Read more
86. What is the study of insects called?
✅ A. Entomology
a: Entomology | b: Botany | c: Herpetology | d: Mycology Read more
87. Which part of the brain helps coordinate balance and movement?
✅ C. Cerebellum
a: Pituitary gland | b: Medulla only | c: Cerebellum | d: Hypothalamus Read more
88. What is the study of fungi called?
✅ D. Mycology
a: Ornithology | b: Ecology | c: Entomology | d: Mycology Read more
89. Which organ produces insulin?
✅ C. Pancreas
a: Thyroid | b: Spleen | c: Pancreas | d: Gallbladder Read more
90. Which biological process produces two genetically similar daughter cells for growth?
✅ C. Mitosis
a: Transcription | b: Meiosis | c: Mitosis | d: Fertilization Read more
91. Which cells help defend the body against infection?
✅ B. White blood cells
a: Platelets | b: White blood cells | c: Red blood cells | d: Adipocytes Read more
92. Which vitamin is essential for normal blood clotting?
✅ D. Vitamin K
a: Vitamin D | b: Vitamin C | c: Vitamin B1 | d: Vitamin K Read more
93. Which organ is primarily responsible for gas exchange in humans?
✅ B. Lungs
a: Spleen | b: Lungs | c: Gallbladder | d: Heart Read more
94. Which part of a plant absorbs most water from soil?
✅ B. Roots
a: Leaves only | b: Roots | c: Flowers | d: Fruits Read more
95. Which pigment gives many plants their green colour?
✅ B. Chlorophyll
a: Haemoglobin | b: Chlorophyll | c: Keratin | d: Melanin Read more
96. Which organ filters blood to produce urine?
✅ A. Kidney
a: Kidney | b: Pancreas | c: Lung | d: Stomach Read more
97. Which molecule carries hereditary information in most organisms?
✅ D. DNA
a: Cellulose | b: ATP | c: Glucose | d: DNA Read more
98. Which blood type is commonly called the universal red-cell donor in emergency contexts?
✅ B. O negative
a: B negative | b: O negative | c: A positive | d: AB positive Read more
99. Which organelle is often called the powerhouse of the cell?
✅ C. Mitochondrion
a: Lysosome | b: Golgi apparatus | c: Mitochondrion | d: Ribosome Read more
100. What is the basic structural and functional unit of life?
✅ A. Cell
a: Cell | b: Organ | c: Organ system | d: Tissue Read more