Question

two brown eyed parents (bb) have a baby. what is the chance the baby is blue eyed? 50% 75% 25% 0 %

Explanation:

Step1: Recall Mendelian Genetics

For a single - gene trait with two alleles, where \(B\) is dominant (brown eyes) and \(b\) is recessive (blue eyes), when both parents are heterozygous (\(Bb\)), we can use a Punnett square to determine the possible genotypes of the offspring.
The Punnett square for \(Bb\times Bb\) is:

	\(B\)	\(b\)
\(b\)	\(Bb\)	\(bb\)

Step2: Determine the Probability of Blue - Eyed (bb) Offspring

From the Punnett square, the possible genotypes are \(BB\), \(Bb\), \(Bb\), and \(bb\). The genotype for blue eyes is \(bb\) (since the blue - eye trait is recessive, it is only expressed when the homozygous recessive genotype is present).
Out of 4 possible genotypes, 1 is \(bb\). So the probability is \(\frac{1}{4}\) or \(25\%\).

Answer:

25% (corresponding to the option with "25%")