How many different kinds of gametes may be produced by an organism with the genotype $RrYy$?

In a typical Mendelian dihybrid cross,one parent is homozygous for both dominant traits and another parent is homozygous for both recessive traits. In the $F_2$ generation,both parental combinations and recombinations appear. The phenotypic ratio of parental combinations to recombinations is

How many pairs of chromosomes are involved in Mendelian dihybrid crosses and dihybrid crosses with linkage,respectively?

Which traits did Mendel consider for his dihybrid cross experiment?

In the $F_2$ generation of a dihybrid cross,how many types of genotypes are produced?

In a plant,red fruit $(R)$ is dominant over yellow fruit $(r)$ and tallness $(T)$ is dominant over shortness $(t)$. If a plant with $RRTt$ genotype is crossed with a plant that is $rrtt$,what will be the phenotypic ratio of the offspring?