Correct Answer: A

Rationale: The correct answer is A: hemoglobin. Hemoglobin is the protein found in red blood cells that is responsible for carrying oxygen from the lungs to the rest of the body. Iron is a crucial component of hemoglobin, binding to oxygen and allowing for its transport.
Choice B, transferrin, is involved in iron transport in the blood but not in oxygen transport.
Choice C, myoglobin, is a protein found in muscle cells that stores oxygen for muscle use, not transportation in the bloodstream.
Choice D, hepcidin, is a peptide hormone that regulates iron absorption in the intestines and iron distribution in the body, but it is not directly involved in oxygen transport.

Correct Answer: C

Rationale: Corrected
Rationale: Protein provides 4 kcal per gram, making it a good source of energy to increase caloric intake. While fiber and water are important for other aspects of health, they do not provide energy like protein does. Vitamins are essential for various bodily functions but do not contribute directly to caloric intake.

Correct Answer: B

Rationale: A casual blood sample of 200 mg/dL or higher in a person with classic symptoms is a diagnostic criterion for diabetes. This choice aligns with the typical clinical presentation of diabetes and is a key diagnostic indicator.

Choices A, C, and D do not accurately reflect the established criteria for diagnosing diabetes, making them incorrect.
Choice A pertains to a fasting plasma glucose level,
Choice C involves a glucose challenge test, and
Choice D refers to HbA1C levels, which are used for monitoring blood sugar control over time, not for diagnosing diabetes.

Correct Answer: D

Rationale: The correct answer is 'none of the above.' Human digestive enzymes like salivary amylase and pancreatic amylase cannot digest fiber. Instead, fiber is fermented by gut bacteria in the large intestine. Cellulase, which is an enzyme produced by some animals and microorganisms, can break down cellulose found in plants, but it is not a human digestive enzyme, making it an incorrect choice in this context.

Correct Answer: D

Rationale: Fluid retention can mask weight loss in ill individuals as the retained fluid adds to body weight, making it difficult to detect true fat or muscle loss. Dehydration (
Choice
A) would actually lead to weight loss rather than masking it. While a large tumor (
Choice
B) could contribute to weight loss, it would not mask the weight loss itself. Drug therapy (
Choice
C) may cause side effects, including weight changes, but it is unlikely to mask significant weight loss in the same way that fluid retention does.