An enzyme is a biomolecule that increases the rate of a chemical reaction. which of the following is true about enzymes?
i. enzymes are not consumed during a chemical reaction.

ii. enzymes are specific to particular molecules.

iii. enzymes increase the energy produced by a chemical reaction.

True: 
I: They aren't consumed, they are natural catalysts so can be used again and again.
II: They are specific to particular molecules, hence different active site shapes, and the lock-and-key model. (go look it up if you don't know what this is, it explains a lot!:) )
False:
III:The same amount of energy will be produced if a enzyme wasn't used, but enzymes SPEED UP the reaction.

Hope this helped!:))

Hey manwere are we to select?