Answer:
The options to this question are unclear, however, the question can still be answered based on general understanding. The answer is:
When elements form compounds, atoms are chemically combined.
Explanation:
Elements are substances made up of a single type of atom. However, elements combine together to form substances called COMPOUNDS, which are substances made up of two or more different atoms. Atoms of elements are joined or linked by certain chemical bonds to form compounds.
According to this question showing a chart of different combinations that some elements form with oxygen, carbon and hydrogen elements combine with oxygen to form CO2, CO and H2O, H2O2 respectively. For this to occur, ATOMS of the ELEMENTS combining MUST be CHEMICALLY BONDED
