Questions: Unit 4 Practice Test Revised Biology - Integrated - A - Premier - 2425 / Unit 4-Genetics-Heredity-Revised Premier 2425 Below is a Punnett Square showing a brown dog with long fur (B8ff) bred with a black dog with short fur (bbFF) What letter(s) belong in the lower left box? BBff Bf Bf Bf Bf bF BbFf BbFf BbFf BbFf bbFF bF BbFf BBFf BbFf BbFf bF BbFf BbFf BbFf BbFf ? BbFf BbFf BbFf BbFf

The answer is the fourth one (〇 bf): bf.

Explanation for each option:

1. bF: This combination represents a black fur (b) and long fur (F) allele. However, the lower left box should represent the combination of alleles from the brown dog with long fur (B8ff) and the black dog with short fur (bbFF). The brown dog contributes a "b" or "B" and an "f" allele, while the black dog contributes a "b" and an "F" allele. The combination "bF" does not match the expected contribution from the brown dog.

2. bb: This combination represents two black fur alleles, which is not possible in this context because the brown dog contributes a "B" or "b" allele, and the black dog contributes a "b" allele. Therefore, "bb" is not a valid combination for the lower left box.

3. BF: This combination represents a brown fur (B) and long fur (F) allele. However, the brown dog with long fur (B8ff) cannot contribute an "F" allele, as it only has "f" alleles for fur length. Therefore, "BF" is not a valid combination for the lower left box.

4. bf: This combination represents a black fur (b) and short fur (f) allele. The brown dog with long fur (B8ff) can contribute a "b" or "B" allele and an "f" allele, while the black dog with short fur (bbFF) can contribute a "b" and an "F" allele. The combination "bf" is a valid combination for the lower left box, as it represents the contribution from both parents.

In summary, the correct letters for the lower left box are "bf".