Alex coral study for her physics exam even though he is stressed about taking his own genetics exam. he is sacrificing his time for coral's benefit, which is an example of altruism. were he to expect coral to return the favor by him study the next day, this would be an example of:

Reciprocal altruism

Explanation:

When you out your time and effort in doing something for someone and you also expect that they will also do that in return this is called reciprocal altruism.

It is like giving back just as someone has given to you .

I do you a favour and you also do me a favour when I am in need of a favour.

Coral helps Alex to study for her physics exam, she can do the same thing by helping him now study for his genetic exam as he also did out his own will for her.

stewards ice box was the purchase of alaska from russia and it was called that because people thought it was not a good idea to purchase alaska

the answer would be c. sediment buildup on continental slope

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