[smt88]

I don't know how you define "respire", but water dissolves and releases gases. Fire is a gas, so it can't "respire" the same way. It is just one gas or another.

As for digestion, water is a powerful solvent that breaks many things down. Fire just heats them up, which may or may not change their chemical structure.

[NavnitG]

Fire takes in Oxygen and gives out CO2. That is respiration. Fire converts fuel into energy. That is digestion.

[smt88]

You do not know what fire is. I'm serious. You should look it up.

For starters, you're confusing combustion with fire.