Correct Answer: D

Rationale: The correct answer is D: To regulate blood glucose. The adrenal glands play a crucial role in regulating blood glucose levels and the body's response to stress. Choice A, 'To regulate metabolism,' is incorrect as the primary role of the adrenal glands is not directly related to metabolism regulation. Choice B, 'To produce bile,' is incorrect because bile is produced by the liver, not the adrenal glands. Choice C, 'To produce red blood cells,' is also incorrect as the production of red blood cells primarily occurs in the bone marrow, not the adrenal glands.

Correct Answer: C

Rationale: The correct answer is C, Nucleus. The nucleus is responsible for storing genetic information in the form of DNA. The DNA within the nucleus controls the activities of the cell by directing the synthesis of proteins and regulating gene expression. Choices A, Ribosome, B, Mitochondrion, and D, Cytoplasm, do not store genetic information. Ribosomes are involved in protein synthesis, mitochondria produce energy for the cell, and cytoplasm is a gel-like substance that houses organelles and where many cellular activities occur.

Correct Answer: B

Rationale: Vitamin D is the correct answer. When the skin is exposed to sunlight, it triggers a process where a form of cholesterol in the skin is converted into vitamin D. This vitamin plays a crucial role in aiding calcium absorption in the gut, which is essential for maintaining strong and healthy bones. Vitamin A (Choice A) is important for vision and immune function but is not produced by sunlight exposure. Vitamin K (Choice C) is known for its role in blood clotting and bone metabolism, but it is not produced by sunlight. Vitamin E (Choice D) is an antioxidant that protects cells from damage but is not synthesized in the skin through sunlight exposure.

Correct Answer: C

Rationale: A graduated cylinder is the most suitable tool to measure the volume of both liquids and solids. It works by measuring the displacement of water when the solid is submerged in the graduated cylinder. Choice A, the triple beam balance, is used to measure mass, not volume. Choice B, using a measuring wheel and mathematical formula, is typically used to measure distance or area, not volume. Choice D, a measuring wheel, is used to measure distance, making it inappropriate for measuring the volume of a solid.

Correct Answer: B

Rationale: During photosynthesis, 12 molecules of NADPH and 18 molecules of ATP are required to reduce 6 molecules of CO2 to glucose. NADPH and ATP are essential energy carriers in the process of photosynthesis. Choice A is incorrect because it underestimates the required molecules of both NADPH and ATP. Choices C and D overestimate the number of molecules needed, making them incorrect answers.