Earth is a system comprised of interacting processes.

Answer (d) the greenhouse effect is primarily caused by car and trucks;

Historians are researchers of the past or people who understand the history of people. with this field, they must possess qualities such as being unbiased, patient, efficient reader, has a knack for logic and critical thinking and reasoning, disciplined, open-minded, resourceful, with good analytical ability, good reasoning skills and problem solving!

Cthat is the answer