When the body uses a substance to synthesize a more complex molecule, that process is irreversible and that substance cannot be restored to its original form.

Correct Answer: A

Rationale: Step 1: When the body synthesizes a more complex molecule, it often involves a series of chemical reactions that lead to the formation of the new molecule. Step 2: These reactions are typically energy-consuming and involve changes in molecular structures that cannot be easily reversed. Step 3: Once a substance is used in these irreversible reactions to form a more complex molecule, it cannot be restored to its original form. Step 4: Therefore, the statement that the process is irreversible and the original substance cannot be restored is true. Summary: Choice A is correct because the process of synthesizing a more complex molecule in the body involves irreversible reactions that permanently change the original substance. Choices B, C, and D are incorrect as they do not accurately describe the irreversible nature of this process.

Correct Answer: B

Rationale: The correct answer is B: FALSE. Bioelectrical impedance is not considered accurate in patients with obesity or diabetes mellitus due to factors such as increased fluid retention and altered tissue characteristics affecting the results. Other choices (A, C, D) are incorrect as bioelectrical impedance is not suitable for body composition assessment in these populations.

Correct Answer: A

Rationale: The correct answer is A: TRUE. ECF volume regulation is essential for maintaining blood pressure through mechanisms like the renin-angiotensin-aldosterone system. On the other hand, ECF osmolarity regulation is crucial to prevent cell shrinkage or swelling due to changes in solute concentrations. Therefore, it is accurate to say that ECF volume is regulated to ensure adequate blood pressure, and ECF osmolarity is regulated to prevent cells from shrinking or swelling. Choices B, C, and D are incorrect as they do not accurately represent the relationship between ECF volume, osmolarity regulation, and their respective purposes in the body.

Correct Answer: A

Rationale: The correct answer is A: TRUE. The renin-angiotensin-aldosterone system works to regulate blood pressure by increasing the reabsorption of Na+ in the distal and collecting tubules of the kidneys. Renin is released in response to low blood pressure, which leads to the formation of angiotensin II, stimulating the release of aldosterone. Aldosterone acts on the distal and collecting tubules to increase Na+ reabsorption, leading to water retention and increased blood volume, ultimately raising blood pressure. Choices B, C, and D are incorrect as they do not provide a detailed explanation of how the renin-angiotensin-aldosterone system functions in regulating blood pressure.

Correct Answer: A

Rationale: Step 1: In a hypertonic extracellular fluid (ECF), there is a higher solute concentration outside the cell. Step 2: Due to osmosis, water will move from an area of low solute concentration (inside the cell) to high solute concentration (outside the cell). Step 3: As a result, cells in a hypertonic ECF tend to lose water to balance the solute concentration. Step 4: Therefore, the statement "Cells in a hypertonic ECF tend to lose water by osmosis" is true. Summary: Choice A is correct because water moves out of the cell in a hypertonic environment. Choices B, C, and D are incorrect as they do not provide a logical explanation based on osmosis principles.