Which of the following statements concerning red blood cells is false?
A) Red cells are biconcave discs.
B) Red cells lack mitochondria.
C) Red cells are about 18 m in diameter.
D) Red cells are specialized for carrying oxygen.
E) Red cells can form stacks called rouleaux.
Question 2
A cation that often acts as a cofactor for enzymes is
A) sodium.
B) potassium.
C) calcium.
D) magnesium.
E) zinc.