单选题Which of the following is true about coral reefs?A They play a significant role in biodiversity.B They account for 25% of the marine life.C More than a quarter of marine life feed on them.D They are threatened by marine life and could be killed.
题目
单选题
Which of the following is true about coral reefs?
A
They play a significant role in biodiversity.
B
They account for 25% of the marine life.
C
More than a quarter of marine life feed on them.
D
They are threatened by marine life and could be killed.