What do plants and animals breathe in during night?

At night animals breathe in Carbon Dioxide because plants reverse their gas exchanging pattern due to the disappearance of the sun. Plants will produce carbon dioxide from oxygen (O2) and glucose (C6H12O6) and the carbon dioxide inhaled will be changed in oxygen + carbon by fission.

C6H12O6 + O2 = CO2 + extra atoms

CO2/fission = O2 + extra C atom