Answer and explanation :
The coral reefs are endangered or exposed by a variety of factors that are hurricane which is a natural phenomenon, diseases and local threats which includes destructive fishing techniques , pollution and global effect of climate change. These pollution is mainly due to sewage and agriculture fishing is destructive because for fishing they usually use cyanide which is very dangerous these are the modern coral reef endangered.
Answer: C.-Water
Explanation: Water is the main component when it comes to wetlands.
Enzymes are protiens that control the speed of chemical reactions in your body therefore without these them the reactions would take place too slow for you to live.
First two don't make sense.
Third is correct.
Last one would be volume.