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:

the father in the first generation probably had the recessive colorblind trait in his x chromosome. if he and his wife both had the colorblind trait, even if she had 1 recessive and 1 dominant, then that trait would be passed on to their kids.

(since you didn't attach the family tree this is just an assumption)

the law of original horizontality explains:   why rocks appear in layers. correct answer: b the law suggests that all rock layers are originally laid down (deposited) horizontally and can later be deformed.   the principle is used by geologists to make assumptions about the relative ages of sedimentary rocks.