C.K.K.K.+5.4

toc =Section 4 (5-4) Rocks From Reefs=

Vocabulary
coral reef- a structure formed from a lot of coral animals atoll- an island that is donut-shaped island far from shore

Living Coral

 * Coral animals are relatives of jellyfish and their size is about the size of the fingernail or smaller.
 * Each one looks like an small sack with a mouth which is surrounded by tentacles.
 * They eat microscopic creatures which is caught by the tentacles.
 * The corals form a skeleton that grows together and that makes the structure called coral reef.
 * They only form in warm, and shallow tropical oceans.
 * They can't grow in cold or low-in-salt oceans.
 * In U.S., they only grow on coasts of southern Florida and Hawaii.
 * There is an tiny algae growing in each coral animal and it provides the substance which coral animals need to live.
 * Algae need sunlight, so most coral reefs occur within 40 meters from surface.
 * There are not enough sunlight below 40 meters from surface.