Is there a photo? I can’t really answer without a photo or anything..?
A reef than surrounds a volcanic island is an : Atoll
Atoll usually takes shapes in a form of ring that surround the areas of volcanic island that consist of corals. It usually only exist in warm waters, so volcanic islands will provide perfect environment for the corals
hope this helps<span />
Explanation:
Well if you think about it...
Venus is to _____. (hot)
So they can't land on it.
Mars is _____. (Not nerarly as hot)
So they can land on it.
So missions to Mars is way safer.
Hope this helps! Sorry if it was not what you were looking for ...