<span>An animal burrows through a rock, causing it to break. This is an example of biological weathering. [ Biological weathering is caused by the growth of roots and burrowing of animals. ]</span>
C. Rich farmland in the river valley is correct, because the Nile River's water kept the ground fertile and made for good agriculture.
Answer:Opportunity cost is the cost of the forgone alternative when a choice is made. In this case, the store made a choice between buying a ship of computers, or buying new phones. It cannot do both because the firm has limited resources.
Explanation: Wrong subject.
