Question

A catalyst is a chemical:

found in leaves
which promotes a chemical reaction
which reacts with sunlight
produced by the chloroplast

Answer 1

A catalyst promotes a chemical reaction. It helps boost it or speed it up.

Answer 2

A catalyst is a chemical ,which promotes a chemical reaction.

Step-by-step explanation:

A catalyst is a substance which speeds up a reaction without it being changed at the end of the reaction. Each reaction normally needs a specific amount of energy i.e. activation energy . The role of catalyst is to reduce that activation energy needed for a reaction occur.