The only thing that removes CO2 from the atmosphere is _____________. Plants use it to make fats, ____________ and ___________. Both plant and animal _____________ put _____ back into the atmosphere.
Carbon from dead _________ and _________ can end up as _______ fuels, when this is _________ it releases carbon. Some dead animal and plants could be ________, be ___________ by microorganisms or be turned into _______ ______________ by humans.