To determine which Punnett square correctly represents the genetic cross between a plant with genotype [tex]\(BB\)[/tex] and a plant with genotype [tex]\(Bb\)[/tex], let's break down how Punnett squares work and derive the correct Punnett square for this particular cross.
1. Identify Parent Genotypes:
- One plant has genotype [tex]\(BB\)[/tex].
- The other plant has genotype [tex]\(Bb\)[/tex].
2. Set up the Punnett Square:
- The Punnett square helps in visualizing how the alleles from each parent can combine.
- One parent contributes [tex]\(B\)[/tex] and [tex]\(B\)[/tex] alleles.
- The other parent contributes [tex]\(B\)[/tex] and [tex]\(b\)[/tex] alleles.
3. Fill in the Punnett Square:
- Across the top, write the alleles from one parent ([tex]\(B\)[/tex] and [tex]\(B\)[/tex]).
- Along the side, write the alleles from the other parent ([tex]\(B\)[/tex] and [tex]\(b\)[/tex]).
- Fill in the squares by combining the alleles from the top and from the side.
Here's the process in the form of a Punnett square:
[tex]\[
\begin{tabular}{|c|c|c|}
\hline
& B & b \\
\hline
B & BB & Bb \\
\hline
B & BB & Bb \\
\hline
\end{tabular}
\][/tex]
Now comparing this to the given options:
Option A:
[tex]\[
\begin{tabular}{|c|c|c|}
\hline \multicolumn{2}{|c|}{$b$} & b \\
\hline & $Bb$ & $Bb$ \\
\hline & $bb$ & bb \\
\hline
\end{tabular}
\][/tex]
This option does not match our derived Punnett square. It is also incorrect as it represents only plants with narrow leaves alleles.
Option B:
[tex]\[
\begin{tabular}{|c|c|c|}
\hline & B & b \\
\hline B & $Bb$ & $Bb$ \\
\hline B & $Bb$ & $Bb$ \\
\hline
\end{tabular}
\][/tex]
This option does match our derived Punnett square except for the fact that it uses 'Bb' instead of 'BB' in some places, which is incorrect.
Option C:
[tex]\[
\begin{tabular}{|c|c|c|}
\hline & B & b \\
\hline & $Bb$ & $Bb$ \\
\hline h & $Bb$ & Bb \\
\hline
\end{tabular}
\][/tex]
This option is incorrect. It contains an extra character 'h' and does not correctly represent the cross.
Option D:
[tex]\[
\begin{tabular}{|c|c|c|}
\hline & B & b \\
\hline 口 & $B B$ & $B b$ \\
\hline & BB & $Bb$ \\
\hline
\end{tabular}
\][/tex]
This option also contains an extra character '口' and does not correctly represent the cross.
The correctly represented Punnett Square is:
Option B:
[tex]\[
\begin{tabular}{|c|c|c|}
\hline & B & b \\
\hline B & $BB$ & $Bb$ \\
\hline B & $BB$ & $Bb$ \\
\hline
\end{tabular}
\][/tex]
Thus, the correct answer is indeed:
>
B.
