Explain two ways in which scientists use fossils to determine environmental change

Hello.  Happy to help.

1)  Coast Lines:  The location of marine fossils can help determine where and when ancient coast lines were in the past.2)  Climates:  Fossils can be used to determine the past climates.  (Was an area cooler or wetter than the present.)

The presence of marine or land fossils indicates whether the land at one time was at the bottom of the ocean or not.

Also, you could mention radioactive dating and relative dating.  I am sure that is mentioned in your curriculum. 

Hope that helps.

Processes above and be sure to mention the movement of electrons and energy as the carbon atom moves from one reaction to another.