Correct Answer: C

Rationale: A complete protein is the term used to describe a protein that contains all the essential amino acids required by the body in the right proportions. This makes choice C the correct answer. Choice A, 'simple,' is incorrect as it does not reflect the concept of essential amino acids. Choice B, 'indispensable,' while related to importance, does not specifically address the presence of all essential amino acids. Choice D, 'complementary,' is also incorrect as it refers to combining proteins to achieve a complete amino acid profile, rather than describing a protein that already contains all essential amino acids.

Correct Answer: A

Rationale: The correct answer is A: Low-density lipoprotein (LDL). LDL is often referred to as 'bad cholesterol' because it can lead to plaque buildup in arteries, increasing the risk of cardiovascular disease. High-density lipoprotein (HDL) is considered 'good cholesterol' as it helps remove LDL from the arteries, reducing the risk of cardiovascular issues. Very low-density lipoprotein (VLDL) and chylomicrons are also lipoproteins that transport fats in the bloodstream, but they are not as strongly associated with an increased risk of cardiovascular disease as LDL.

Correct Answer: C

Rationale: The correct answer is C: Small intestine. The majority of lipid digestion occurs in the small intestine, where bile and pancreatic lipase are active. Lipids are broken down into fatty acids and glycerol in the small intestine. Choices A, B, and D are incorrect because the mouth and stomach play minor roles in lipid digestion, and the large intestine is mainly responsible for absorbing water and electrolytes from the indigestible food residues.

Correct Answer: A

Rationale: Albumin is the correct answer. It is a plasma protein that helps maintain osmotic pressure, thereby playing a vital role in regulating fluid balance in the body. Fibrinogen is involved in blood clotting, not fluid balance. Hemoglobin is responsible for oxygen transport in red blood cells, not fluid balance. Collagen is a structural protein found in connective tissues, not directly involved in fluid balance.

Correct Answer: D

Rationale: The correct answer is D, rennin. Rennin is the enzyme in infants responsible for coagulating milk, which aids in the digestion process. Choice A, casein, is a milk protein and not an enzyme. Choices B and C, pepsinogen and trypsin, are digestive enzymes but are not specifically involved in coagulating milk in infants.