Correct Answer: C

Rationale: Peripheral vasodilation is the widening of blood vessels near the surface of the skin, allowing more blood to flow near the skin's surface. This process enhances heat loss primarily through radiation. Radiation is the transfer of heat energy in the form of electromagnetic waves. Conduction involves direct contact between objects, convection involves the transfer of heat through fluid or gas, and evaporation involves the phase change of a liquid to a gas, which cools the surface.

Correct Answer: A

Rationale: The correct answer is 'Hematocrit.' Hematocrit is the measurement of the percentage of red blood cells in whole blood. It is used to diagnose conditions such as anemia and dehydration. Choice B, 'Hemoglobin,' measures the amount of hemoglobin in the blood, not the percentage of red blood cells. Choice C, 'Mean corpuscular volume,' measures the average volume of a red blood cell, not the percentage of red blood cells. Choice D, 'Reticulocyte count,' measures the percentage of young red blood cells in the blood, not the percentage of red blood cells.

Correct Answer: A

Rationale: The correct answer is the Distal convoluted tubule (DCT). The DCT is the part of the nephron closest to the collecting duct, where the final adjustments to electrolyte and fluid balance are made. Bowman's Capsule is located at the beginning of the nephron, where filtration of blood occurs. The Afferent Arteriole brings blood to the glomerulus for filtration. The Proximal Convoluted Tubule (PCT) is situated after the Bowman's Capsule and is not the part closest to the collecting duct.

Correct Answer: C

Rationale: Calcium plays an essential role in the clotting of blood by being involved in several steps of the coagulation process. It is necessary for the conversion of prothrombin to thrombin, which is a crucial step in forming blood clots. Sodium, magnesium, and potassium do not directly participate in the clotting cascade and are not associated with the coagulation process. Therefore, the correct answer is calcium.

Correct Answer: C

Rationale: The correct answer is potassium. High levels of potassium in the blood, known as hyperkalemia, can lead to cardiac arrhythmias by affecting the electrical activity of the heart. This can disrupt the normal rhythm of the heart and lead to serious complications. Chloride, phosphorus, and sodium imbalances are not typically associated with cardiac arrhythmias, making them incorrect choices.