In $F_2$ generation,a phenotypic ratio of $1:1:1:1$ exhibits

In Mendel's dihybrid cross experiment,what is the number of offspring with the $RRYY$ genotype in the $F_2$ generation?

What is the phenotypic ratio of a test cross in the $F_1$ generation of a dihybrid cross?

Determine the number of possible gametes produced from an organism with the genotype $RrYy$.

In peas,tallness is dominant over dwarfness and red colour of flowers is dominant over the white colour. When a tall plant bearing red flowers was pollinated with a dwarf plant bearing white flowers,the different phenotypic groups were obtained in the progeny in numbers mentioned against them:
Tall,Red $= 138$
Tall,White $= 132$
Dwarf,Red $= 136$
Dwarf,White $= 128$
Mention the genotypes of the two parents and of the four offspring types.

In a dihybrid cross,$80$ plants are obtained. The ratio of homozygous and heterozygous plants shall be: