Why does DNA replication have to occur before cell division? Explain what would happen if it did not occur

DNA replication needs to occur because existing cells divide to produce new cells. Each cell needs a full instruction manual to operate properly. So the DNA needs to be copied before cell division so that each new cell receives a full set of instructions!

DNA replication has to occur before cell division in order to make new copies.

Explanation:

The DNA needs to be copied before cell division so that each new cell can recieve a full new set of "instructions".