A.) The cell prepares for cell division.
<span>No
DNA is synthesized in the middle part of Interphase, which is usually denoted S in the series G1 - S - G2 </span><span>"There are 3 stages of interphase: G1 in which the cell grows and functions normally. Once it grows too large it enters the synthesis (S) phase. In S phase the cell makes exact copies of its DNA. It is now ready for G2 phase where it makes sure all of its chromosomes and organelles are ready for mitosis."</span>
First, he should measure how long it takes for the liquid to become clear if X and Y are mixed together. Then, he should measure how long it takes if he also adds substance A to X and Y. He will find out if substance A is a catalyst. hope this helps :)