"$A$ given compound always contains the same proportion of elements" is a statement of $-$

$5.06 \ g$ of pure cupric oxide $(CuO)$ on complete reduction gives $4.04 \ g$ of metallic copper. In another experiment,$1.3 \ g$ of metallic copper is dissolved in nitric acid and the resulting solution is carefully dried to yield $1.63 \ g$ of $CuO$. Which law of chemical combination is illustrated by these results?

The law of multiple proportions is illustrated by the two compounds:

$1 \, L$ of $N_2$ combines with $3 \, L$ of $H_2$ to form $2 \, L$ of $NH_3$ under the same conditions. This illustrates the:

Black oxide of copper and red oxide of copper contain $79.9\%$ and $88.8\%$ of metal respectively. This data illustrates the law of:

Write about Dalton's Atomic Theory.