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

The phenotypic ratio in the $F_{2}$ generation of a dihybrid cross is

In a dihybrid cross,out of $16$ plants obtained in the $F_2$ generation,the number of distinct genotypes is:

When a tall plant with round seeds $(TTRR)$ is crossed with a dwarf plant with wrinkled seeds $(ttrr)$,the $F_1$ generation consists of tall plants with round seeds. How many types of gametes will the $F_1$ generation plant produce?

What will be the phenotypic ratio of the offspring obtained from a cross between $Aabb$ and $Ccdd$?

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?