1.  True or False? Coral reefs are an exclusive ecological club that only a few species use.

False! Many thousands of fish and marine invertebrate species live in and around coral reefs. Up to 25% of all ocean life may be associated with coral reef ecosystems at some point in their life cycle.

2.  What is the coral that makes coral reefs?

a.  a type of undersea flower

b.  an animal related to worms

c.  a species of seaweed

d.  an animal related to sea jellies

e.  a type of lava that bubbles up from under the ocean surface and hardens to create reefs

The correct answer is d. Coral are animals related to sea jellies and sea anemones. Some coral species build reefs and some do not. 

Individual corals are called polyps. Reef-building coral polyps extract calcium from the ocean around them and use it to build support structures around them. Over time as layers of coral polyps die, their calcium structures build up and form reefs. 

The living coral polyps on a coral reef live on the outside layer of the reef. A big coral reef may take many thousands of years of coral polyps to build up into the larger structures recognizable as reefs.

3. What do coral eat?

a.  fish sticks

b.  sugar

c.  sushi 

d.  fish sandwiches

The correct answer is b. The coral polyps that build reefs have algae growing inside of them that photosynthesize, creating sugars from chemical reactions and light. The coral polyp provides a home for the algae and the algae creates food for the coral polyp. This is called a symbiotic relationship. 

The coral polyps have tentacles that can also be used for grabbing small organisms like plankton out of the water around them.