Isn't essential for photosynthesis.

Nitrogen, oxygen is by-product and carbon dioxide turns into oxygen.

Answer;

Nitrogen

Nitrogen is not essential for photosynthesis.

Explanation;Photosynthesis is the process by which green plants make their own food using energy from the sun, together with carbon dioxide and water.The reactants of photosynthesis include, water, carbon dioxide and light energy, to produce glucose, and oxygen as a by product.Photosynthesis takes place in two stages, the light-dependent reactions and the light-independent reactions. During the light dependent-reactions light energy is used to split water molecules into hydrogen ions and oxygen atoms. while in the light independent reactions carbon fixation takes place, where carbon dioxide is converted to organic compounds.

Land marks is ruler of the world i just wanna let you kno that you are really smart