[Campbell Biology P.984] Which statement accurately describes a characteristic of a specific... | Practice Question

Which statement accurately describes a characteristic of a specific cellular element in blood, based on the provided text?

  • A: Leukocytes are primarily responsible for oxygen transport and are generally found only within the circulatory system.
  • B: Platelets are complete cells with nuclei, primarily functioning in immune responses.
  • C: Mature mammalian erythrocytes lack a nucleus and mitochondria, relying on anaerobic metabolism, and transport approximately 1 billion O2 molecules per cell.
  • D: There are typically 250 million leukocytes per microliter of human blood, a number that decreases during infection.

Explanation

The text explicitly states that mature mammalian erythrocytes lack nuclei and mitochondria, generate ATP exclusively by anaerobic metabolism, and one erythrocyte can transport about 1 billion O2 molecules. Leukocytes are for defense and can be found outside the circulatory system. Platelets are fragments without nuclei and function in clotting. Normal leukocyte counts are 5,000-10,000 per µL and increase during infection.