The statement that describes the function of a catalyst is that it speeds up a chemical reaction (option D).
<h3>What is a catalyst?</h3>
A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process.
A catalyst can also be said to speed up the rate at which a chemical reaction occurs by lowering the activation energy required for the reaction to start.
Therefore, the statement that describes the function of a catalyst is that it speeds up a chemical reaction.
