In humans, having more than five fingers or toes is dominant over having exactly five finger or toes. Which of the following situations would most likely result in exactly half of a couple's offspring having six digits and half of them having five?

A.Both parents are homozygous for the recessive trait
B. Both parents are heterozygous
C. One parent is heterozygous while the other is homozygous for the recessive tratit.
D. One parent is homozygous for the recessive trait while the other is homozygous for the dominant trait.
Is the answer a?

No, if both parents homozygous recessive, all offspring will be recessive.

Use Punnett square.

https://www.google.com/search?client=safari&rls=en&q=punnett+square+worksheet&ie=UTF-8&oe=UTF-8&gws_rd=ssl

No, the answer is not A.

To understand which situation would most likely result in exactly half of a couple's offspring having six digits and half having five, we need to consider the inheritance pattern of the trait.

In this case, having more than five fingers or toes (six digits) is dominant over having exactly five fingers or toes. Let's represent the trait for having six digits as "D" and the trait for having five digits as "d".

A. Both parents are homozygous for the recessive trait (dd): In this situation, both parents only carry the trait for having five digits. Since having six digits is dominant, none of their offspring will have six digits. So, the answer is not A.

B. Both parents are heterozygous (Dd): In this situation, both parents carry one copy of the dominant trait for having six digits (D) and one copy of the recessive trait for having five digits (d). When these parents reproduce, there is a 25% chance that both parents will pass on the recessive trait (d) to their offspring, resulting in five digits, while there is a 25% chance that both parents will pass on the dominant trait (D), resulting in six digits. Therefore, half of the offspring (50%) are expected to have six digits, and half are expected to have five digits, as desired. So, the answer could be B.

C. One parent is heterozygous (Dd) while the other is homozygous for the recessive trait (dd): In this situation, the heterozygous parent (Dd) carries one copy of the dominant trait for having six digits (D) and one copy of the recessive trait for having five digits (d), while the homozygous recessive parent (dd) carries two copies of the recessive trait for having five digits. As in situation B, there is a 25% chance that both parents will pass on the recessive trait (d) to their offspring, resulting in five digits. However, there is no chance of the dominant trait (D) being passed on to the offspring, so none of the offspring will have six digits. Therefore, the answer is not C.

D. One parent is homozygous for the recessive trait (dd) while the other is homozygous for the dominant trait (DD): In this situation, the homozygous recessive parent (dd) carries two copies of the recessive trait for having five digits, while the homozygous dominant parent (DD) carries two copies of the dominant trait for having six digits. Since both parents carry only one type of the trait, all their offspring will inherit two copies of the dominant trait (DD) and will have six digits. Therefore, the answer is not D.

Based on the analysis above, the most likely situation that would result in exactly half of a couple's offspring having six digits and half having five digits is when both parents are heterozygous (B).