GMAT Critical Reasoning (CR) | Re: One of the limiting factors in human physical performance is

What confused me with the correct answer, even though by the structure it makes most sense, is that I was looking for a sentence that would have the same meaning as the one in bold face. Since it stated that muscles cannot get more oxygen as it is, I eliminated the correct answer because it was talking about muscles absorbing oxygen, the opposite of the boldface.
So what I got from this is not to confuse "serves the same function" with "has similar meaning"

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