please draw the monohybrid and dihybrid cross of a plantand also tell genotypic and phenotypic ratio of the crosses??

 

 

In a monohybrid cross, only one trait is under study while in a dihybrid cross two traits are under study. 

Lets consider that a homozygous tall plant (TT) and a heterozygous tall plant is crossed (Tt).

After formation of gametes, this type of cross ir made.

Here is an example of dihybrid cross.

The genotypic ratio and phenotypic ratio vary depending on the genotype of parents. For Mendelian ratios of F1 and F2 generation you may refer to the answer provided by your friend. I would just like to correct him that phenotypic ratio in a dihybrid cross of F2 generation is 9:3:3:1