1.What weakens coral exoskeletons? Excess salt

Excess CO2

Excess sunlight

Excess fishes

2.A quarter of marine life lives in which type of ecosystem?

fish

zooxanthellae

coral reef

ocean

3.What do corals provide for zooxanthellae?

food

sunlight

a source of oxygen

a protective area

1 is excess CO2

2 is coral reef

3 both a protective area and food in the way of nutrients though if you only can choose one go with protective area

Explanation:

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.

what bodys are there orbiting?