What can be said about the components of a compound?

The choice that indicates components of a compound can only be separated by chemical means is correct because compounds are formed when two or more elements chemically bond together in fixed proportions. This chemical bonding results in the formation of a new substance with properties that are different from the individual elements. To separate a compound into its constituent elements, a chemical reaction must be performed, such as electrolysis for water (H2O) to yield hydrogen and oxygen.

In contrast, components of a mixture can be separated by physical means, such as filtration or distillation, and retain their individual properties. Because compounds involve a chemical change and the formation of a new substance, they do not exhibit these characteristics. This is why the other options do not accurately describe the nature of compounds. Thus, the distinction between the methods of separation and the retention of properties is crucial in understanding the characteristics of compounds.