Correct Answer: A

Rationale: The liver's main role in digestion is to produce bile, a substance that aids in the breakdown and absorption of fats in the small intestine. Bile emulsifies fats, helping enzymes break them down into smaller molecules for easier absorption in the digestive tract. Therefore, the correct answer is A: 'To produce bile.' Storing glucose, secreting digestive enzymes, and detoxifying harmful substances are functions of the liver, but they are not primarily related to digestion.

Correct Answer: B

Rationale: The primary function of the kidneys in the urinary system is to filter blood to remove waste products and excess fluids, which are then excreted as urine. Kidneys act as a filtration system, removing waste like urea, excess salts, and toxins. While the kidneys do play a role in regulating blood pressure by secreting renin and maintaining electrolyte balance by adjusting the levels of sodium, potassium, and other ions in the blood, their main and essential function is filtration and waste removal, making choice B the correct answer.

Correct Answer: A

Rationale: The correct answer is A. The primary function of the large intestine is to absorb water from the remaining indigestible food matter and form solid waste (feces) for excretion. This process helps in reabsorbing water and electrolytes, resulting in the formation of feces by compacting the waste material. Choices B, C, and D are incorrect because the large intestine is not responsible for producing digestive enzymes, secreting hormones, or transporting nutrients. These functions are typically associated with other parts of the digestive system.

Correct Answer: B

Rationale: The correct answer is B: Hyoid. The hyoid bone is the only bone in the body that does not articulate with any other bones. It is located in the neck and supports the tongue and other muscles involved in swallowing and speech. The scapula articulates with the clavicle and humerus, the radius with the ulna and humerus, and the femur with the pelvis and tibia. Choices A, C, and D are incorrect because they all articulate with other bones in the body.

Correct Answer: B

Rationale: The primary function of the heart is to pump oxygenated blood and nutrients throughout the body, supplying cells with vital substances. Choice A is incorrect as the kidneys are responsible for filtering blood. Choice C is incorrect as waste removal is primarily handled by organs like the kidneys and liver. Choice D is incorrect as regulating body temperature is mainly controlled by mechanisms such as sweating and shivering, not the heart.