When crossing a true breeding white mouse with a true breeding brown mouse your friend tells you she recovered all black mice. But then when she crosses the F1 mice to each other she recovered 28 black mice, 8 brown mice, and 13 white mice. Can you help her explain these results? (Type out the cross and include genotypes of as many mice as possible. What phrase best describes this phenomenon? How many genes are involved are they linked or unlinked? Etc.)