21. Which of the following best describes active transport?

a) Movement of molecules from high to low concentration

b) Movement of molecules against a concentration gradient using energy

c) Diffusion of water through a semi-permeable membrane

d) Movement of molecules through osmosis

Correct Answer: b) Movement of molecules against a concentration gradient using energy

22. Which of the following is a feature of prokaryotic cells?

a) They have a nucleus

b) They have membrane-bound organelles

c) They have circular DNA

d) They have chloroplasts

Correct Answer: c) They have circular DNA

23. Which component of the cell membrane helps to transport molecules across the membrane?

a) Lipids

b) Proteins

c) Carbohydrates

d) DNA

Correct Answer: b) Proteins

24. Which enzyme is responsible for breaking down starch into simple sugars?

a) Lipase

b) Amylase

c) Protease

d) Lactase

Correct Answer: b) Amylase

25. Which organ in the human body produces bile?

a) Stomach

b) Gall bladder

c) Liver

d) Pancreas

Correct Answer: c) Liver

26. Which part of the nervous system controls reflex actions?

a) Brain

b) Spinal cord

c) Peripheral nerves

d) Cerebellum

Correct Answer: b) Spinal cord

27. Which of the following is a waste product of respiration?

a) Oxygen

b) Carbon dioxide

c) Glucose

d) Starch

Correct Answer: b) Carbon dioxide

28. In which part of the plant does photosynthesis primarily occur?

a) Stem

b) Root

c) Leaf

d) Flower

Correct Answer: c) Leaf

29. What is the function of the stomata in plant leaves?

a) To absorb water

b) To transport nutrients

c) To allow gas exchange

d) To store carbohydrates

Correct Answer: c) To allow gas exchange

30. Which of the following best describes the process of transpiration?

a) Movement of water from roots to leaves

b) Evaporation of water from leaves

c) Production of glucose in leaves

d) Absorption of carbon dioxide by leaves

Correct Answer: b) Evaporation of water from leaves

31. Which blood vessel carries oxygenated blood from the lungs to the heart?

a) Pulmonary artery

b) Aorta

c) Pulmonary vein

d) Vena cava

Correct Answer: c) Pulmonary vein

32. What is the main function of the large intestine?

a) Absorption of water

b) Absorption of nutrients

c) Digestion of proteins

d) Production of bile

Correct Answer: a) Absorption of water

33. Which part of the brain controls balance and coordination?

a) Cerebrum

b) Cerebellum

c) Medulla

d) Hypothalamus

Correct Answer: b) Cerebellum

34. What is the primary function of the kidney in the human body?

a) To produce blood cells

b) To excrete waste products and regulate water balance

c) To store glucose

d) To control body temperature

Correct Answer: b) To excrete waste products and regulate water balance

35. Which blood component is responsible for transporting oxygen?

a) White blood cells

b) Platelets

c) Plasma

d) Red blood cells

Correct Answer: d) Red blood cells

36. Which type of microorganism causes malaria?

a) Bacteria

b) Virus

c) Protist

d) Fungus

Correct Answer: c) Protist

37. Which part of the flower produces pollen?

a) Stigma

b) Ovary

c) Anther

d) Sepal

Correct Answer: c) Anther

38. What is the role of insulin in the human body?

a) To regulate blood glucose levels

b) To break down fats

c) To digest proteins

d) To control water balance

Correct Answer: a) To regulate blood glucose levels

39. Which vitamin is essential for blood clotting?

a) Vitamin A

b) Vitamin C

c) Vitamin K

d) Vitamin D

Correct Answer: c) Vitamin K

40. What is the primary role of the mitochondria in cells?

a) To store genetic material

b) To produce energy

c) To synthesize proteins

d) To regulate water balance

Correct Answer: b) To produce energy

41. Which gas is used in the process of respiration?

a) Oxygen

b) Nitrogen

c) Carbon dioxide

d) Hydrogen

Correct Answer: a) Oxygen

42. Which process in plants involves the conversion of light energy into chemical energy?

a) Transpiration

b) Respiration

c) Photosynthesis

d) Osmosis

Correct Answer: c) Photosynthesis

43. What is the function of the cilia in the respiratory system?

a) To absorb oxygen

b) To trap dust and bacteria

c) To produce mucus

d) To remove carbon dioxide

Correct Answer: b) To trap dust and bacteria

44. Which type of immunity is gained by vaccination?

a) Passive immunity

b) Active immunity

c) Natural immunity

d) Temporary immunity

Correct Answer: b) Active immunity

45. In which part of the cell does protein synthesis occur?

a) Nucleus

b) Ribosome

c) Mitochondria

d) Golgi apparatus

Correct Answer: b) Ribosome

46. Which organ is responsible for filtering blood in the human body?

a) Liver

b) Heart

c) Kidneys

d) Lungs

Correct Answer: c) Kidneys

47. What is the role of the pancreas in digestion?

a) To absorb nutrients

b) To produce digestive enzymes

c) To produce insulin

d) To neutralize stomach acid

Correct Answer: b) To produce digestive enzymes

48. What is the main function of hemoglobin?

a) To digest food

b) To carry oxygen

c) To fight infections

d) To transport glucose

Correct Answer: b) To carry oxygen

49. Which process describes the division of a diploid cell into two genetically identical daughter cells?

a) Meiosis

b) Mitosis

c) Fertilization

d) Binary fission

Correct Answer: b) Mitosis

50. Which part of the brain controls involuntary actions like heartbeat and breathing?

a) Cerebrum

b) Medulla

c) Hypothalamus

d) Cerebellum

Correct Answer: b) Medulla