Respuesta :

The correct answer is Sulfur Hexafluoride
it’s an inert gas that is known to be six times heavier than the air we breathe. While Helium being lighter makes our voice higher, SF6 makes our voice deeper. The sound travels slower in denser gases which is why our voice will come out deeper and rather slow.
kgirl633

Answer:

Sulfur hexafluoride

Explanation:

It is heavier than air that we breathe so it has an opposite effect.

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