Which law did Mendel propose based on his dihybrid cross experiment?

The ratio $1:1:1:1$ is observed in:

In Mendel's dihybrid cross,what is the ratio of offspring possessing homozygous dominant and homozygous recessive genotypes in the $F_2$ generation,which shows a phenotypic ratio of $9:3:3:1$?

Which of the following gametes are produced by an individual with genotype $RrYy$?

If a plant having yellow and round seeds was crossed with another plant having green and wrinkled seeds,then the $F_{1}$-progeny are in the ratio:

In Mendel's dihybrid cross,what is the probability of obtaining a plant that is heterozygous for both traits (in $/16$)?