Correct Answer: B

Rationale: The lens of the eye is responsible for focusing light onto the retina. It plays a crucial role in bending light rays to ensure that they converge on the retina, enabling clear vision. The cornea helps in focusing light, but the final adjustment and fine-tuning occur through the lens. The retina receives the focused light and converts it into neural signals for the brain to interpret. The pupil, on the other hand, controls the amount of light entering the eye by dilating or constricting.

Correct Answer: B

Rationale: The central nervous system comprises the brain and spinal cord, responsible for processing and transmitting information. The retina, though part of the eye, is an extension of the central nervous system. However, the heart is part of the circulatory system, responsible for pumping blood throughout the body.
Therefore, the correct answer is the heart as it is not a component of the central nervous system.

Correct Answer: C

Rationale: The main function of the respiratory system is to absorb oxygen from the air into the bloodstream and remove carbon dioxide from the body. Oxygen is essential for cellular respiration, the process through which cells generate energy. Carbon dioxide is a waste product expelled during this process.
Choice A, '
To transport nutrients,' is incorrect as the respiratory system is not primarily responsible for transporting nutrients.
Choice B, '
To regulate body temperature,' is incorrect as the respiratory system's main role is not temperature regulation.
Choice D, '
To produce energy,' is incorrect because while oxygen obtained through respiration is used in the energy production process, the respiratory system itself does not directly produce energy.

Correct Answer: B

Rationale: The adrenal glands function to produce hormones such as adrenaline and cortisol. These hormones play essential roles in regulating metabolism, immune response, and the body's response to stress.
Therefore, the correct answer is that the adrenal glands produce hormones.

Choices A, C, and D are incorrect as regulating blood sugar is primarily done by the pancreas, producing red blood cells is the function of the bone marrow, and filtering blood is carried out by the kidneys, not the adrenal glands.

Correct Answer: B

Rationale: The gallbladder's primary function in digestion is to store and concentrate bile produced by the liver. Bile is essential for the digestion and absorption of fats in the small intestine. While the gallbladder does not produce bile (
Choice
A) or secrete digestive enzymes (
Choice
D), it plays a crucial role in storing and releasing bile when needed.
Therefore, the correct answer is B.