The law of dihybrid cross proves which of the following?

When a cross is made between a tall plant with yellow seeds $(TtYy)$ and a tall plant with green seeds $(Ttyy)$,what proportions of phenotypes in the offspring could be expected to be:
$(a)$ Tall and green.
$(b)$ Dwarf and green.

The following experiment is a dihybrid cross performed by Mendel. In which of the following are the green and wrinkled traits observed in the pea plants?

In plants,red fruit $(R)$ is dominant over yellow fruit $(r)$ and tall height $(T)$ is dominant over dwarf height $(t)$. If a plant with genotype $RRTt$ is crossed with a plant with genotype $RRTt$,what will be the phenotype of the offspring?

In Mendel's experiments with garden pea,round seed shape $(RR)$ was dominant over wrinkled seeds $(rr),$ and yellow cotyledon $(YY)$ was dominant over green cotyledon $(yy).$ What are the expected phenotypes in the $F_{2}$-generation of the cross $RRYY \times rryy$?

What is the genotype of the $F_1$ generation offspring obtained in a dihybrid cross?