Question

describe about nucleus in 2 to 3 lines as it is for my sister

Answer 1

 nucleus is a membrane-enclosed organelle found in eukaryotic cells.Cell nuclei contain most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes.

Answer 2

it is a central part of atom .
it contain neutron and protons .
atom has a positive charge due to proton present in nucleus.