441. 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
Biology MCQs – Page 23
442. Which organ is primarily responsible for gas exchange in humans?
✅ B. Lungs
a: Spleen | b: Lungs | c: Gallbladder | d: Heart Read more
443. 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
444. Which part of a plant absorbs most water from soil?
✅ B. Roots
a: Leaves only | b: Roots | c: Flowers | d: Fruits Read more
445. Which pigment gives many plants their green colour?
✅ B. Chlorophyll
a: Haemoglobin | b: Chlorophyll | c: Keratin | d: Melanin Read more
446. Which organ filters blood to produce urine?
✅ A. Kidney
a: Kidney | b: Pancreas | c: Lung | d: Stomach Read more
447. 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
448. Which molecule carries hereditary information in most organisms?
✅ D. DNA
a: Cellulose | b: ATP | c: Glucose | d: DNA Read more
449. Which organelle is often called the powerhouse of the cell?
✅ C. Mitochondrion
a: Lysosome | b: Golgi apparatus | c: Mitochondrion | d: Ribosome Read more
450. What is the basic structural and functional unit of life?
✅ A. Cell
a: Cell | b: Organ | c: Organ system | d: Tissue Read more
451. Practice check: Choose the correct biology answer: which process reduces chromosome number to form gametes?
✅ B. Meiosis
a: Budding | b: Meiosis | c: Binary fission | d: Mitosis Read more
452. Practice check: Choose the correct biology answer: which gas is released by plants during photosynthesis?
✅ D. Oxygen
a: Methane | b: Ammonia | c: Carbon monoxide | d: Oxygen Read more
453. Practice check: Choose the correct biology answer: which plant tissue transports sugars?
✅ D. Phloem
a: Cuticle | b: Stomata | c: Xylem | d: Phloem Read more
454. Practice check: Choose the correct biology answer: which plant tissue transports water upward?
✅ C. Xylem
a: Cortex only | b: Phloem | c: Xylem | d: Epidermis Read more
455. Practice check: Choose the correct biology answer: which blood component helps form clots?
✅ B. Platelets
a: Red blood cells | b: Platelets | c: Alveoli | d: Neurons Read more
456. Practice check: Choose the correct biology answer: which part of the eye controls the amount of light entering?
✅ D. Iris
a: Optic nerve | b: Retina | c: Cornea only | d: Iris Read more
457. Practice check: Choose the correct biology answer: what is the largest organ of the human body?
✅ B. Skin
a: Brain | b: Skin | c: Liver | d: Lung Read more
458. Practice check: Choose the correct biology answer: which molecule is the main immediate energy currency of cells?
✅ B. ATP
a: RNA | b: ATP | c: DNA | d: Starch Read more
459. Practice check: Choose the correct biology answer: which structure controls what enters and leaves a cell?
✅ B. Cell membrane
a: Cell wall only | b: Cell membrane | c: Chromosome | d: Nucleolus Read more
460. Practice check: Choose the correct biology answer: which organisms make their own food using sunlight in most ecosystems?
✅ B. Producers
a: Primary consumers | b: Producers | c: Predators | d: Decomposers only Read more