The F1 generation of a cross between a red cock and white hen were all red because the gene for the
Answer Details
In genetics, the physical appearance or trait expressed by an organism is determined by the alleles it inherits from its parents. Alleles are different versions of the same gene, and they can be either dominant or recessive. In this case, the F1 generation (first filial generation) of a cross between a red cock and white hen were all red, which means that they inherited the red allele from the red cock parent. The gene for the red color is dominant over the gene for white color, which is recessive. Therefore, in the F1 generation, all the offspring expressed the dominant allele for red color and not the recessive allele for white color, which did not segregate. Thus, the correct option is "red color was dominant".