Question

speeds up the rate of a chemical reaction
catalyst
sucrose
protein
substrate

Explanation:

A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. Sucrose is a sugar (a disaccharide), protein is a macromolecule made of amino acids, and a substrate is the reactant in an enzyme - catalyzed reaction. So the substance that speeds up the rate of a chemical reaction is a catalyst.

Answer:

A. Catalyst