Answer :
Let's carefully evaluate each of the given statements based on the provided Punnett squares.
### Punnett Squares:
#### First Generation:
[tex]\[ \begin{array}{|c|c|c|} \hline & t & t \\ \hline T & Tt & Tt \\ \hline T & Tt & Tt \\ \hline \end{array} \][/tex]
#### Second Generation:
[tex]\[ \begin{array}{|c|c|c|} \hline & T & t \\ \hline T & TT & Tt \\ \hline t & Tt & tt \\ \hline \end{array} \][/tex]
### Analyzing Each Statement:
1. Plants with short stems are homozygous for that trait.
- For a plant to have short stems, it must have the genotype "tt", which is a homozygous recessive genotype.
- This statement is true.
2. Plants with tall stems are always homozygous for that trait.
- A plant with tall stems can have either "TT" (homozygous dominant) or "Tt" (heterozygous) genotype.
- Therefore, this statement is false.
3. Both parent plants in the second generation are heterozygous.
- In the second generation Punnett square, the parent plants used are "T" and "t", which represent the genotypes "TT" and "Tt" respectively.
- Not both of them are heterozygous.
- This statement is false.
4. Both parent plants in the second generation are homozygous.
- In the second generation Punnett square, the parent plants are "T" (which includes the homozygous "TT") and "t" (which includes the heterozygous "Tt"). Only one of the parents is homozygous.
- This statement is false.
Given the analysis, the true statements are:
- Plants with short stems are homozygous for that trait.
Therefore, the correct answers are:
- Plants with short stems are homozygous for that trait.
### Punnett Squares:
#### First Generation:
[tex]\[ \begin{array}{|c|c|c|} \hline & t & t \\ \hline T & Tt & Tt \\ \hline T & Tt & Tt \\ \hline \end{array} \][/tex]
#### Second Generation:
[tex]\[ \begin{array}{|c|c|c|} \hline & T & t \\ \hline T & TT & Tt \\ \hline t & Tt & tt \\ \hline \end{array} \][/tex]
### Analyzing Each Statement:
1. Plants with short stems are homozygous for that trait.
- For a plant to have short stems, it must have the genotype "tt", which is a homozygous recessive genotype.
- This statement is true.
2. Plants with tall stems are always homozygous for that trait.
- A plant with tall stems can have either "TT" (homozygous dominant) or "Tt" (heterozygous) genotype.
- Therefore, this statement is false.
3. Both parent plants in the second generation are heterozygous.
- In the second generation Punnett square, the parent plants used are "T" and "t", which represent the genotypes "TT" and "Tt" respectively.
- Not both of them are heterozygous.
- This statement is false.
4. Both parent plants in the second generation are homozygous.
- In the second generation Punnett square, the parent plants are "T" (which includes the homozygous "TT") and "t" (which includes the heterozygous "Tt"). Only one of the parents is homozygous.
- This statement is false.
Given the analysis, the true statements are:
- Plants with short stems are homozygous for that trait.
Therefore, the correct answers are:
- Plants with short stems are homozygous for that trait.