Atom refers to a tiny particle, which is the basic building block of all the substances and whose properties determine the characteristics of an element made up of only of those atoms.
All the living and nonliving matter in this world are made up of atoms and elements. Everything in the universe is matter, and matter comprises elements. Some of the elements are important to living things.
Elements are formed by atoms, and atoms comprise protons, electrons, and neutrons. The number of protons in an element's atom signifies the identity of the element.
The answer is letter A.
<span>Organelles and other cellular material are held within a cell by a cellular membrane. These membranes are what consist of a cell's exterior.
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