Correct Answer: A

Rationale: The statement is TRUE. Sickle cell disease is caused by a genetic mutation in the hemoglobin gene, leading to an abnormal amino acid sequence. This results in the production of abnormal hemoglobin molecules, causing red blood cells to become sickle-shaped. This inherited condition is a classic example of a genetic error affecting the amino acid sequence, making choice A the correct answer. Choices B, C, and D are incorrect as they do not accurately reflect the nature of sickle cell disease.

Correct Answer: D

Rationale: Villi and microvilli in the GI tract serve to increase the surface area of the small intestine, aiding in the absorption of nutrients into the bloodstream. Choices A, B, and C are incorrect as villi and microvilli are primarily involved in enhancing absorption, not in producing bile, killing bacteria, or producing vitamin K.

Correct Answer: A

Rationale: The correct answer is Marasmus. Marasmus is a severe form of protein-energy malnutrition (PEM) that leads to muscle wasting, hanging skin, delayed growth, and changes in saliva. These symptoms are commonly seen in vulnerable populations such as children, homeless individuals, older adults, and substance abusers. Kwashiorkor, on the other hand, is characterized by edema, a distended belly, and skin lesions. Anemia is a condition characterized by a low red blood cell count, leading to fatigue and weakness. Noma is a severe infection affecting the face, particularly the mouth and jaw area.

Correct Answer: B

Rationale: An LDL cholesterol level of less than 110 mg/dL is considered acceptable and healthy for children and adolescents. This level helps reduce the risk of cardiovascular diseases. Choices A, C, and D are incorrect because an LDL cholesterol level below 110 mg/dL is the recommended target for children and adolescents to maintain good heart health.

Correct Answer: B

Rationale: The correct answer is B, milk. Milk is known for being one of the best dietary sources of calcium, essential for bone health and various bodily functions. Soy products, cereal grains, and dark green vegetables are good sources of calcium as well, but milk generally has a higher calcium content compared to these options.