Problem: - 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 - Eventually there is nothing living in the water and it is unusable - What might be the first step of the process?

A: Pollution enters natural water sources such as rivers and lakes

Problem: - Remove any ice cubes currently in the tray - Fill the tray with cold water - Ensure the tray is evenly filled to an appropriate level - Open the freezer - Place the tray in the freezer - Close the freezer door - Wait. What might be the first step of the process?

A: Get the ice tray

Problem: - The heated water evaporates - The salt is left behind - The evaporated water condenses on a cold surface - The evaporated water is collected - The process is repeated - More salt is removed from the water. What might be the first step of the process?

A: Water is heated

Problem: - The liver uses enzymes to clean the blood - The cleaned blood is expelled - The liver creates bile from the items filtered - The liver takes energy and stores it as glycogen - The bile is sent to the intestines. What might be the first step of the process?

A:
The liver takes in blood from the rest of the body