Question

What waste product does aerobic organisms release into the environment that plants use during photosynthesis

Answer 1

Answer: Carbon Dioxide (CO2)

Aerobic organisms (like us!) are organisms that need oxygen. That means they consume oxygen ($O_{2}$)and release carbon dioxide ($CO_{2}$).

That carbon dioxide is the waste product that is taken up by plants during photosynthesis to create more oxygen and sugars (as "food" for the plants). This is seen in the equation for photosynthesis, where the things that are consumed by plants are on the left of the arrow, and the things produced are on the right:
6CO2 + 6H2O + light energy ==> C6H12O6 + 6O2