According to Dalton's atomic theory,atoms of an element are

Which of the following pairs of substances illustrates the Law of Multiple Proportions?

$n_1 \ g$ of substance $X$ reacts with $n_2 \ g$ of substance $Y$ to form $m_1 \ g$ of substance $R$ and $m_2 \ g$ of substance $S$. The reaction is represented as $X + Y \rightarrow R + S$. What is the relationship between the mass of the reactants and the mass of the products?

Choose the incorrect statement about Dalton's Atomic Theory.

Assertion : Atoms can neither be created nor destroyed.
Reason : Under similar conditions of temperature and pressure,equal volumes of gases do not contain equal numbers of atoms.

When the volume is expressed,what does the law of definite proportions represent?