Correct Answer: D

Rationale: The primary function of the liver related to digestion is to filter and detoxify byproducts of digestion, including toxins and metabolic waste products. While the liver does produce bile and convert waste ammonia into urea, these functions are not directly related to digestion. Storing bile is mainly done by the gallbladder, not the liver.

Correct Answer: B

Rationale: The correct answer is B: Adhesion. Water's polarity allows it to dissolve many substances due to its ability to adhere to and interact with other molecules, making it an effective solvent. Cohesion refers to water molecules sticking together, molarity is a measure of concentration, and dilution refers to the process of reducing the concentration of a solute in a solution, none of which directly relate to water's role as a universal solvent.

Correct Answer: B

Rationale: The correct answer is B: Vein. Veins carry blood back to the heart from various parts of the body, functioning as the vessels that return blood to the heart. Arteries, on the other hand, carry blood away from the heart to different parts of the body to deliver oxygen and nutrients. Capillaries are tiny blood vessels where the exchange of gases, nutrients, and waste products occurs between the blood and tissues. Lymphatic vessels are part of the lymphatic system, responsible for maintaining fluid balance and aiding in immunity. Therefore, the correct choice is B as it directly relates to the blood flow back to the heart.

Correct Answer: B

Rationale: The correct answer is B: Liver. The liver is responsible for producing bile, which aids in fat digestion. The pancreas produces digestive enzymes, the gallbladder stores bile produced by the liver, and the stomach primarily secretes gastric acid for digestion. Therefore, choices A, C, and D are incorrect as they do not directly produce bile.

Correct Answer: B

Rationale: Cartilage is the correct answer as it provides flexible support and protection in the trachea. Cartilage is specifically designed to maintain the trachea's shape and prevent it from collapsing during breathing. Bone is a rigid tissue, not found in the trachea, and would not provide the necessary flexibility for breathing. Collagen is a structural protein but does not offer the same support and flexibility as cartilage in this context. Keratin is a protein that forms structures like hair and nails, and it is not present in the trachea to provide protection.