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
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You can usually tell the difference between a caldera and crater by studying <span>a feature's size and formation. In terms of size, a caldera is often relatively larger than ordinary craters. A caldera is so big that it causes explosive eruptions. In terms of formation, a caldera is a large depression caused when a magma chamber is emptied. A crater is a bowl-like formation at the top of volcanoes where lava comes out.</span>
The another name for the equatorial coordinate system is B. Celestial.
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