Multiple choice

Down's syndrome is a genetically inherited dominant trait. If two parents are heterozygous for it, what are the chances that they will have a child who has this trait in his or her phenotype?

  1. 25%

  2. 50%

  3. 75%

  4. 100%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

There is a 50% chance that the children will be heterozygous (Aa) and a 25% chance that they will be homozygous dominant (AA). Children with either of these genotypes will have this trait expressed in their phenotypes.

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