Explanation:
In a monohybrid cross between two black Angus cattle that are both heterozygous for the color trait (Bb), there are three possible genotypes:
1. BB - Homozygous dominant for black color
2. Bb - Heterozygous for black color
3. bb - Homozygous recessive for red color (black is dominant over red)
Now, let's determine the phenotypic ratio:
1. BB genotype: The individual will be black in color. This is the dominant phenotype.
2. Bb genotype: The individual will also be black in color, as the presence of one dominant allele (B) is sufficient to express the black color. This is the dominant phenotype.
3. bb genotype: The individual will be red in color, as it has two copies of the recessive allele (b). This is the recessive phenotype.
Therefore, the phenotypic ratio of the offspring from a monohybrid cross between two black Angus cattle that are heterozygous for the black color trait would be:
2 black (BB and Bb) : 1 red (bb)
The simplest way to represent this is a ratio of 2:1, or approximately 66.7% black and 33.3% red
