POINTS Aliah conducted an experiment to determine respiratory rates during different activities. She counted the number of breaths per minute. Aliah noted that the number of breaths increases as physical activity increases. Why is there an increase in the number of breaths per minute as activity increases?

A) As activity increases, breathing becomes more efficient.

B) As activity increases, the rate of the heart beating increases.

C) As activity increases, the oxygen needs of cells increase.

D) As activity increases, more oxygen is exhaled.