Problem: -  Bread is exposed to the elements - Bread absorbs water from the air - Bread absorbs warmth from the air - Dust particles with mold spores fall on bread - Mold spores start to consume the bread for energy  What might be the last step of the process?

A: Mold colonies grow until they are visible.


Problem: -  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?

A: The lungs expel through the nose or mouth back into the environment.


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: -  Humans are born as babies - Babies become infants - Infants become children - Children learn skills - Children become teenagers - Teenagers undergo puberty - Teenagers become adults - Adults have children - Adults become elderly  What might be the last step of the process?

A: