What do you think is a challenge for cliff swallows living in this new environment that would explain an increase in the number of swallow roadkill seen in the 1970s, after the highway was completed?

carbon atoms, hydrogen, oxygen, and nitrogen.

the cost of mining is extremely low compared to the money earned from mining, creating income to improve the environment.

the correct answers are;

a. the rock was made from more than one type of material.

e. layers of hot liquids in the rock cooled and solidified at different temperatures.

these are the two options that are related to the statement given above.