question_answer

DIRECTIONS: Read the passage (s) given below and answer the questions that follow. Passage - 2 We obtain energy by aerobic respiration. But anaerobic respiration can sometimes take place in our muscles during vigorous physical exercise when oxygen gets used up faster in the muscle cells than can be supplied by the blood. Why do we inhale more oxygen when we run fast?

A) we breathe fast

B) Our heart beats faster

C) We need more energy

D) all of these