Answer: Option (a) is the correct answer.
Explanation:
A molecule is defined as the substance in which same or different atoms chemically combine together.
For example, [tex]Cl_{2}[/tex], [tex]CH_{4}[/tex], [tex]CCl_{4}[/tex] are all molecules.
When we break down a molecule into its constituent atoms then properties of its atoms remain the same.
Hence, we can conclude that molecules are the smallest units an element can be broken down into and still retain its defining properties.
