An atom is the most basic form
of life. Also, an atom can represent an element. The element can be different
such as oxygen, nitrogen, everything that is present in the periodic table. We
can also classify an element into a metal, nonmetal or metalloid. The very core
of an atom is the nuclei. Protons and neutrons are present inside the nuclei. A combination of elements is a compound. When formed,
they can be very stable. The answer is D.
