Smaller Single-Celled Organisms Do Not Require as High an Oxygen

Multiple Choice

Smaller single-celled organisms do not require as high an oxygen concentration as larger ones do.This is because the smaller cells

A) have a faster metabolic rate per unit mass.
B) have a slower metabolic rate per unit mass.
C) have a lower surface area-to-volume ratio.
D) have a greater surface area-to-volume ratio.
E) divide more quickly than small cells do.