- Waste products are deposited in the blood - Blood is carried to the kidneys through the renal arteries - The kidneys contain filters inside - The filters capture the waste products - The waste is combined with water to make urine - The urine leaves the kidney and is collected in the bladder What might be the last step of the process?
Ans: The cleaned blood is returned to the body.

- Human industry produces chemical compounds - Chemical compounds rise into the air - Chemical compounds mix with elements in clouds - The affected rain falls to the earth What might be the last step of the process?
Ans: The affected rain can harm natural and man-made objects because of its acidic content.

- Water gets into cracks in rocks - The water freezes into ice - The cracks expand - Over time the rocks split What might be the last step of the process?
Ans: The rocks are now in smaller pieces.

- The liver removes toxins from the blood - Liver also cleans blood that has just been enriched with vitamins and minerals during digestion - Liver processes the good stuff into forms that the rest of the body can use - Waste or stuff your body doesn't need can be carried by bile back into the intestine or into the kidneys - The liver also produces a digestive juice called bile that helps the body absorb fat into the bloodstream What might be the last step of the process?
Ans: The liver also stores extra carbohydrates as glycogen for the body to use as fuel when needed.