Question

when a cell reproduce,what happens to its DNA

Answer 1

In preparation for cell division, the cell makes a replica of its entire DNA.
This happens during the S, or synthesis, phase of the cellcycle.
Mitosis is the division of one cell into two cells that each has a nucleus and the same amount of DNA as the originalcell

Answer 2

Here's your answer looking for

As we know that the nucleus contains the genetic material of the cell.

And when cell reproduce then the DNA start condensing.
And after that it condensed to form a chromosomes.

So when the cell reproduce then the DNA starts condensing and then formed a chromosomes.

Hope you are satisfied with my answer