Problem: -  Oxygen enters the body through the mouth or nose - The oxygen travels into the lungs - The oxygen binds to hemoglobin proteins within erythrocytes (red blood cells) - The erythrocytes are pumped through the body by the heart  What might be the last step of the process?

A: All cells receive the oxygen.


Problem: -  Coal is mined out of the ground - Coal is pulverized into fine powder - The coal is mixed with hot air - The coal and hot air are blown into a boiler - The coal and hot air burn over a fire - Highly purified water is pumped through pipes in the boiler - The water turns into steam - The steam presses against turbines - The turbines spin  What might be the last step of the process?

A: Electricity is produced.


Problem: -  You eat food - Your stomach digests the food - Sugars from food enter your bloodstream - Insulin helps turn sugars into energy  What might be the last step of the process?

A: Insulin helps your body store the energy in fat, muscle and liver cells


Problem: -  Networks of trees start forming - The trees die off - The dead material provides nutrients for more trees - The rising trees provide shelter - And more organisms begin to thrive  What might be the last step of the process?

A:
The ecosystem known as a forest is made.