AP BIOLOGY

Detailed explanation-1: -A cross between roan bull (Ww) and red cow (WW) produces roan and red phenotypes in 1:1 ratio. A cross between roan bull (Ww) and white cow (ww) produces roan and white phenotypes in 1:1 ratio. The proportions of roan cows in the offspring of each group of cow is 2, 1, 1. Thus, the correct answer is option A.

Detailed explanation-2: -Answer and Explanation: The offspring from a mating a roan bull with a white cow will be roan and white in a 1:1 ratio.

Detailed explanation-3: -If a red cow is bred to a white bull, all offspring are roan, which have red and white hairs intermixed on the hide. This is an example of codominance.

Detailed explanation-4: -In shorthorn cattle, when a red bull (RR) is crossed with a white cow (WW), all the offspring are roan-a spotted, red and white or milky red color.