Question

what is nucleus how is it useful

Answer 1

nucleus is a dense round body present in the centre of the cell.
it acts as control room of the cell
if nucleus is not present in the cell it will die

Answer 2

The nucleus is the membrane enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material.The nucleus is like the 'Brain' of the cell. It controls what happens inside the cell. It also has DNA in it.