Why does each cell have 2 copies of each gene is it because when cell dived the copy the nucleus and the genes present in the nucleus?
A copy comes from one each of the sperm and egg cell (animals). During meiosis, the genetic material is halved so that the gamete (sex cell) has half the genetic information in. During fertilisation, both these halves fuse to give 100% DNA, half from each parent.
During mitosis, all of this information is copied exactly so that each daughter cell has the same DNA as the last.
Hope that answers your question; if not, please let me know.