Answer:
a)
R R
R RR RR
r Rr Rr
Genotypic ratio: RR : Rr = 2 : 2 = 1: 1
Phenotypic ratio: homozygous red bull (RR) : heterozygous red cow (Rr) = 2:2 = 1: 1
b)
R r
R RR Rr
r Rr rr
Genotypic ratio: RR : Rr:rr = 1:2:1
Phenotypic ratio: homozygous red bull (RR) : heterozygous red cow (Rr) : homozygous white bull (rr) = 1: 2: 1
c)
Xr Yr
Xr Xr Xr Xr Yr
Xr Xr Xr Xr Yr
Genotypic ratio: Xr Xr: Xr Yr = 2: 2 = 1: 1
Phenotypic ratio: homozygous white cow (Xr Yr) : heterozygous white bull (Xr Yr) = 2: 2 = 1: 1
Explanation:
a)
First cross is between a a homozygous red bull (RR) and a heterozygous red cow (Rr)
This shows that "Red" color is a dominant trait
So the cross between Rr and RR is
R R
R RR RR
r Rr Rr
Genotypic ratio: RR : Rr = 2 : 2 = 1: 1
Phenotypic ratio: homozygous red bull (RR) : heterozygous red cow (Rr) = 2:2 = 1: 1
b)
Cross between a heterozygous red bull (Rr) and a heterozygous red cow (Rr)
R r
R RR Rr
r Rr rr
Genotypic ratio: RR : Rr:rr = 1:2:1
Phenotypic ratio: homozygous red bull (RR) : heterozygous red cow (Rr) : homozygous white bull (rr) = 1: 2: 1
c)
Cross between a homozygous white bull (rr) and a homozygous white cow (rr)
Xr Yr
Xr Xr Xr Xr Yr
Xr Xr Xr Xr Yr
Genotypic ratio: Xr Xr: Xr Yr = 2: 2 = 1: 1
Phenotypic ratio: homozygous white cow (Xr Yr) : heterozygous white bull (Xr Yr) = 2: 2 = 1: 1