The calcium hydroxide experiment demonstrates that

A)there is a much lower concentration of O₂ in expired air than in atmospheric air.
B)there is a much higher concentration of CO₂ in expired air than in atmospheric air.
C)there is a much higher concentration of O₂ in expired air than in atmospheric air.
D)there is a much lower concentration of CO₂ in expired air than in atmospheric air.
E)the concentrations of CO₂ in expired air and atmospheric air are approximately equal.