Question: -  Magma comes up to the surface of the earth - The magma cools - Particles inside the magma move closer together - Crystals are formed  What might be the last step of the process?
Answer: The crystals contain minerals.

Question: -  You inhale - Your diaphragm moves down - Your lungs have more room - Your lungs fill with air - You exhale - Your diaphragm moves back up - Carbon dioxide is exhaled  What might be the last step of the process?
Answer: You start the process over again.

Question: -  Pollution enters natural water sources such as rivers and lakes - The pollution negatively affects the water quality - The pollution negatively affects the health of plants and animals - The plants and animals have shorter, less healthy lives - The plants and animals do not reproduce very well - The number of plants and animals decreases over time - The quality of water gets worse and worse as there are no plants or animals to clean it  What might be the last step of the process?
Answer:
Eventually there is nothing living in the water and it is unusable