Answer:
Protons and neutrons which packed tightly into central core of the atom.
Explanation:
Atoms are composed of three subatomic particle; electron, proton and neutron. Electrons are negatively charged, protons are positively charged whereas neutrons are neutral, hence does not have any charge.
Out of three, protons and neutrons are present in the nucleus of the atom.
Nucleus is the central part of the atom possessing most of the mass of the atom. In the nucleus, protons and neutrons are tightly packed with the help of nuclear force.
Electrons are present around the nucleus also called electron cloud.
Therefore, nucleus are composed of protons and neutrons which packed tightly into central core of the atom
