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A particular plant has two alleles that control the length of its stem. [tex]\( T \)[/tex] represents the dominant allele for a tall stem, and [tex]\( t \)[/tex] represents the recessive allele for a short stem. Based on the Punnett squares, which two statements are true about the genotype of the plant's stem length?

[tex]\[
\begin{array}{|c|c|c|}
\hline
\text{First Generation} & t & t \\
\hline
T & Tt & Tt \\
\hline
T & Tt & Tt \\
\hline
\end{array}
\][/tex]

[tex]\[
\begin{array}{|c|c|c|}
\hline
\text{Second Generation} & T & t \\
\hline
T & TT & Tt \\
\hline
t & Tt & tt \\
\hline
\end{array}
\][/tex]

- Plants with short stems are homozygous for that trait.
- Plants with tall stems are always homozygous for that trait.
- Both parent plants in the second generation are heterozygous.
- Both parent plants in the second generation are homozygous.



Answer :

GinnyAnswer
Let's analyze the provided information and determine the correct statements based on the Punnett squares for the first and the second generation.

### First Generation

Punnett Square:
[tex]\[ \begin{tabular}{|c|c|c|} \hline & t & t \\ \hline T & Tt & Tt \\ \hline T & Tt & Tt \\ \hline \end{tabular} \][/tex]

In the first generation:
- All offspring have the genotype [tex]\( Tt \)[/tex], which means all have tall stems since [tex]\( T \)[/tex] (tall) is the dominant allele.

### Second Generation

Punnett Square:
[tex]\[ \begin{tabular}{|c|c|c|} \hline & T & t \\ \hline T & TT & Tt \\ \hline t & Tt & tt \\ \hline \end{tabular} \][/tex]

In the second generation:
- There are four possible genotypes: [tex]\( TT \)[/tex], [tex]\( Tt \)[/tex], [tex]\( Tt \)[/tex], and [tex]\( tt \)[/tex].
- The phenotypes of these genotypes are as follows:
- [tex]\( TT \)[/tex] - Homozygous tall
- [tex]\( Tt \)[/tex] - Heterozygous tall
- [tex]\( tt \)[/tex] - Homozygous short

### Analysis of Statements

1. Plants with short stems are homozygous for that trait.
- True, because the only genotype that results in short stems is [tex]\( tt \)[/tex], which is homozygous recessive.

2. Plants with tall stems are always homozygous for that trait.
- False, because plants with tall stems can be either [tex]\( TT \)[/tex] (homozygous dominant) or [tex]\( Tt \)[/tex] (heterozygous).

3. Both parent plants in the second generation are heterozygous.
- False, the Punnett square shows that the parents in the second generation are [tex]\( T \)[/tex] and [tex]\( t \)[/tex] (derived from the first generation which produced only [tex]\( Tt \)[/tex]) therefore, one of the parents would necessarily be heterozygous [tex]\( Tt \)[/tex].

4. Both parent plants in the second generation are homozygous.
- False, as explained above, neither can both parents be [tex]\( TT \)[/tex] or [tex]\( tt \)[/tex] in the second generation since the first generation produced all [tex]\( Tt \)[/tex].

### Conclusion
The correct statement(s) about the genotype of the plant's stem length are:
1. Plants with short stems are homozygous for that trait.

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