Answer: Option (1) is the correct answer.
Step-by-step explanation:
A compound is defined as the substance in which different elements are chemically combine together in a fixed ratio by mass.
For example, chemical formula of ammonia is
.
Here, in
the atoms are present in 1:3 ratio.
A compound can be divided into its constituent or simpler substances by chemical means.
On the other hand, an element is defined as a substance which contains atoms of only one type.
For example, Al, Sb, Ar etc are all elements.
An element can never be divided into its constituent parts.
Thus, we can conclude that out of the given options ammonia is the substance which can be broken down by chemical means.