What immediate physical effect does Mars's near-vacuum pressure have on body fluids?

Answer

Water rapidly boils away or sublimates directly into vapor, even at freezing temperatures.

The surface pressure on Mars is less than one percent of Earth's sea-level pressure, which causes water to immediately transition out of its liquid state, an essential first step in the preservation process.

What immediate physical effect does Mars's near-vacuum pressure have on body fluids?
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