Biology
bezawit
17

A runner is three quarters of the way through a marathon. Which systems are working to maintain oxygen levels for the runner's muscles? a. integumentary, excretory, nervous, endocrine b. circulatory, excretory, nervous, endocrine c. respiratory, excretory, nervous, endocrine d. circulatory, respiratory, nervous, endocrine

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(1) Answers
Cesarivan022

The correct answer is D. circulatory, respiratory, nervous, endocrine  The other systems mentioned in the first three examples don't maintain oxygen levels at that body strain level.

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