input question: -  You breathe oxygen into your body through the nose or mouth - The oxygen travels to the lungs through the windpipe - The air sacs in the lungs send the oxygen into the blood stream - The carbon dioxide in the blood stream is transferred to the air sacs  What might be the last step of the process????
output answer: The lungs expel through the nose or mouth back into the environment.

input question: -  Greenhouse gases are released into the air by human activities - The earth changes energy from the sun into heat - Heat rises from the ground - Greenhouse gas molecules in the atmosphere prevent the heat from going into space - The temperature of the earth increases - The temperature continues to rise and melts the polar ice caps  What might be the last step of the process????
output answer: The temperature rises even faster.

input question: -  Plants and animals long ago died - They are buried under layers of soil - Pressure builds over time - The remains liquefy  What might be the last step of the process????
output answer: The carbon atoms rearrange to become a new substance.

input question: -  Coal is burned - Sulfur in the coal combines with oxygen to form sulfur oxides - The sulfur oxides are released into the atmosphere - The sulfides combine with oxygen in the atmosphere to form sulfur trioxide - The sulfur trioxide reacts with water in the atmosphere to form sulfuric acid, a very strong acid  What might be the last step of the process????
output answer:
The sulfuric acid makes the rain acidic