Correct Answer: B

Rationale: The correct answer is B: Insulin. Insulin, produced by the pancreas, plays a crucial role in regulating blood sugar levels by facilitating glucose uptake into cells. Thyroxine, adrenaline, and cortisol do not directly regulate blood sugar levels. Thyroxine is produced by the thyroid gland and regulates metabolism. Adrenaline and cortisol are hormones involved in stress responses and do not have a primary function in blood sugar regulation. Understanding the functions of these hormones is crucial in differentiating their roles in the body and identifying the specific hormone responsible for blood sugar regulation.

Correct Answer: B

Rationale: Bronchitis is the correct answer. It is the inflammation of the bronchi, which are the air passages in the lungs. Bronchitis typically presents with symptoms such as a persistent cough, mucus production, and sometimes difficulty breathing. Pneumonia, on the other hand, is an infection that causes inflammation in the air sacs of the lungs, not specifically the bronchi. Emphysema is a chronic lung condition characterized by the gradual destruction of the air sacs in the lungs, resulting in breathing difficulties. Pleurisy refers to inflammation of the pleura, the lining around the lungs and chest cavity, causing chest pain when breathing or coughing.

Correct Answer: C

Rationale: The small intestine is the primary site for nutrient absorption in the human digestive system. It is where the majority of digestion and absorption of nutrients from food occurs. The walls of the small intestine are lined with tiny finger-like projections called villi, which increase the surface area available for absorption. Nutrients such as carbohydrates, proteins, fats, vitamins, and minerals are absorbed through the walls of the small intestine and into the bloodstream to be transported to cells throughout the body for energy and other functions. The esophagus is a muscular tube that connects the throat to the stomach and plays a role in swallowing, not nutrient absorption. The large intestine primarily absorbs water and electrolytes from the remaining indigestible food matter after the absorption of nutrients in the small intestine. The stomach mainly functions in the mechanical and chemical breakdown of food through muscular contractions and the secretion of digestive enzymes.

Correct Answer: B

Rationale: The correct answer is B: 'To secrete digestive enzymes.' The pancreas plays a crucial role in the digestive system by secreting digestive enzymes that aid in breaking down food in the small intestine. These enzymes help in the digestion of carbohydrates, fats, and proteins, facilitating the absorption of nutrients from the digested food. Choice A is incorrect because the pancreas is not responsible for storing bile; the gallbladder stores bile. Choice C is incorrect because the pancreas secretes enzymes for protein digestion but does not digest proteins itself. Choice D is incorrect as the absorption of nutrients primarily occurs in the small intestine, not in the pancreas.

Correct Answer: C

Rationale: The nucleus is the organelle responsible for controlling the activities of the cell. It contains the cell's genetic material (DNA) and serves as the command center of the cell, regulating gene expression and directing cellular activities. The nucleus plays a crucial role in cell growth, metabolism, and reproduction. While the Golgi apparatus is involved in processing and packaging proteins, the mitochondria are responsible for producing energy in the form of ATP, and ribosomes are involved in protein synthesis, none of these organelles have the primary function of controlling the activities of the cell like the nucleus does. Therefore, the correct answer is the nucleus.