Reefs are built by _____, tiny, soft-bodied animals related to jeyllyfish.
fish
sea horses
starfish
coral polyps
Coral reefs are _____ when people take coral from the reef to make things.
built up
helped
damaged
protected
Global warming has caused many reefs to become ____.
better
bigger
sick
healthy
If we take care of reefs, they can _____ or come back.
tear down
rebuild
break
die
