Answer: C. It's a zone that is the right distance from a star for liquid water to be possible.
Explanation:
The definition of “habitable zone” means the distance from a star at which liquid water exists. Habitable zones are known to be neither too hot nor too cold for life. An example is: If Earth were at the same distance Pluto is, then liquid water wouldn't exist, because it would freeze, and become ice. Now, if Earth was at the same distance Venus is, then liquid water wouldn't exist, because it would become too hot and dry, which means that any organism won't be able to survive in those circumstances.
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