combustion
It is given off during respiration but I don't know about photosynthesis. I think oxygen is actually given off by photosynthesis.
the two substances that are given of during respiration and is use in photosynthesis is carbon dioxide and water.
Water and carbon dioxide is given off in cellular respiration
Carbon Dioxide
Carbon Dioxide
Combustion
O2 is given off during photosynthesis and combined with sugar to give off CO2 during respiration.
no
Carbon Dioxide
Carbon dioxide
6CO2 and 6H2O