Accordingtothefourthparagraph,

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问题: Accordingtothefourthparagraph,saunagivestheskinahealthyglowbecause________.

A: poresarecleanedbysweat.

B:waterislostbysweating.

C:bloodmovestothesurfaceforheatexchange.

D:theheartpumpsharderandfaster.