Problem: -  Acid rain enters the atmosphere and lands - Makes water acidic - Kills fish - Kills the soils in trees  What might be the last step of the process?

A: Leaves are also harmed.


Problem: -  He air we breathe contains oxygen and other gases - Once in the lungs, oxygen is moved into the bloodstream and carried through your body - At each cell in your body, oxygen is exchanged for a waste gas called carbon dioxide - Your bloodstream then carries this waste gas back to the lungs where it is removed from the blood stream and then exhaled  What might be the last step of the process?

A: Your lungs and respiratory system automatically perform this vital process, called gas exchange


Problem: -  Animals and plants die in soft soil or mud - Sediment builds up over the remains - The remains decompose, leaving only trace amounts - The remaining parts over the years are replaced with mineral  What might be the last step of the process?

A: A fossil is formed


Problem: -  Get an ice cube tray - Fill the tray with cool water - Place the tray in the freezer - Leave the tray in the freezer for a few hours - Take they tray out of the freezer  What might be the last step of the process?

A: