Final answer:
The probability of a child being normal when one parent is normal and the other is heterozygous for an extra finger trait is 25%.
Explanation:
The probability of the first child being normal:
- Parental Genetics: Parent 1 is normal, and Parent 2 is heterozygous for the extra finger trait.
- Determining Probabilities: Use Punnett squares to analyze genetic probabilities.
- Probability Calculation: The probability of the first child being normal is 25% (b).
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