Answer :
Let's analyze the question step-by-step:
Firstly, we need to understand the Punnett squares provided for the first and second generations:
### First Generation Punnett Square
[tex]\[ \begin{array}{|c|c|c|} \hline & t & t \\ \hline T & Tt & Tt \\ \hline T & Tt & Tt \\ \hline \end{array} \][/tex]
This shows that the first generation plants have genotypes:
- [tex]\( Tt \)[/tex]
- [tex]\( Tt \)[/tex]
- [tex]\( Tt \)[/tex]
- [tex]\( Tt \)[/tex]
All possible offspring in the first generation are heterozygous ([tex]\( Tt \)[/tex]). Since [tex]\( T \)[/tex] (tall stem) is dominant over [tex]\( t \)[/tex] (short stem), all the first-generation plants will have tall stems.
### Second Generation Punnett Square
[tex]\[ \begin{array}{|c|c|c|} \hline & T & t \\ \hline T & TT & Tt \\ \hline t & Tt & tt \\ \hline \end{array} \][/tex]
This shows that the second generation plants have genotypes:
- [tex]\( TT \)[/tex]
- [tex]\( Tt \)[/tex]
- [tex]\( Tt \)[/tex]
- [tex]\( tt \)[/tex]
From the second-generation Punnett square, we see the following phenotypes for stem length:
- [tex]\( TT \)[/tex]: Tall stem (homozygous)
- [tex]\( Tt \)[/tex]: Tall stem (heterozygous)
- [tex]\( Tt \)[/tex]: Tall stem (heterozygous)
- [tex]\( tt \)[/tex]: Short stem (homozygous)
Now let's analyze the statements:
1. Plants with short stems are homozygous for that trait.
- Correct. A plant will have short stems if and only if it has the genotype [tex]\( tt \)[/tex], which is homozygous recessive.
2. Plants with tall stems are always homozygous for that trait.
- Incorrect. Plants with tall stems can be either homozygous dominant ([tex]\( TT \)[/tex]) or heterozygous ([tex]\( Tt \)[/tex]). Thus, tall-stemmed plants are not always homozygous.
3. Both parent plants in the second generation are heterozygous.
- Incorrect. The second generation Punnett square is created by crossing [tex]\( Tt \)[/tex] (tall stem, heterozygous) and [tex]\( Tt \)[/tex] (tall stem, heterozygous). As a result, both parent plants are heterozygous.
4. Both parent plants in the second generation are homozygous.
- Incorrect. As mentioned, both parent plants in the second generation are [tex]\( Tt \)[/tex] (heterozygous).
So, the correct statements are:
- "Plants with short stems are homozygous for that trait."
Given the step-by-step explanation, this concludes the detailed solution.
Firstly, we need to understand the Punnett squares provided for the first and second generations:
### First Generation Punnett Square
[tex]\[ \begin{array}{|c|c|c|} \hline & t & t \\ \hline T & Tt & Tt \\ \hline T & Tt & Tt \\ \hline \end{array} \][/tex]
This shows that the first generation plants have genotypes:
- [tex]\( Tt \)[/tex]
- [tex]\( Tt \)[/tex]
- [tex]\( Tt \)[/tex]
- [tex]\( Tt \)[/tex]
All possible offspring in the first generation are heterozygous ([tex]\( Tt \)[/tex]). Since [tex]\( T \)[/tex] (tall stem) is dominant over [tex]\( t \)[/tex] (short stem), all the first-generation plants will have tall stems.
### Second Generation Punnett Square
[tex]\[ \begin{array}{|c|c|c|} \hline & T & t \\ \hline T & TT & Tt \\ \hline t & Tt & tt \\ \hline \end{array} \][/tex]
This shows that the second generation plants have genotypes:
- [tex]\( TT \)[/tex]
- [tex]\( Tt \)[/tex]
- [tex]\( Tt \)[/tex]
- [tex]\( tt \)[/tex]
From the second-generation Punnett square, we see the following phenotypes for stem length:
- [tex]\( TT \)[/tex]: Tall stem (homozygous)
- [tex]\( Tt \)[/tex]: Tall stem (heterozygous)
- [tex]\( Tt \)[/tex]: Tall stem (heterozygous)
- [tex]\( tt \)[/tex]: Short stem (homozygous)
Now let's analyze the statements:
1. Plants with short stems are homozygous for that trait.
- Correct. A plant will have short stems if and only if it has the genotype [tex]\( tt \)[/tex], which is homozygous recessive.
2. Plants with tall stems are always homozygous for that trait.
- Incorrect. Plants with tall stems can be either homozygous dominant ([tex]\( TT \)[/tex]) or heterozygous ([tex]\( Tt \)[/tex]). Thus, tall-stemmed plants are not always homozygous.
3. Both parent plants in the second generation are heterozygous.
- Incorrect. The second generation Punnett square is created by crossing [tex]\( Tt \)[/tex] (tall stem, heterozygous) and [tex]\( Tt \)[/tex] (tall stem, heterozygous). As a result, both parent plants are heterozygous.
4. Both parent plants in the second generation are homozygous.
- Incorrect. As mentioned, both parent plants in the second generation are [tex]\( Tt \)[/tex] (heterozygous).
So, the correct statements are:
- "Plants with short stems are homozygous for that trait."
Given the step-by-step explanation, this concludes the detailed solution.