To determine which statements are accurate, let's analyze the given information and apply our knowledge of genetics and Punnett squares.
### First Generation:
1. The first generation Punnett square shows the cross:
[tex]\[
\begin{array}{|c|c|c|}
\hline
& t & t \\
\hline
T & Tt & Tt \\
\hline
T & Tt & Tt \\
\hline
\end{array}
\][/tex]
For the first generation:
- The parent plants are T (dominant) and t (recessive) allele bearers.
- All offspring (100%) are heterozygous (Tt), each showing the dominant trait (tall stems).
### Second Generation:
2. The second generation Punnett square shows the cross:
[tex]\[
\begin{array}{|c|c|c|}
\hline
& T & t \\
\hline
T & TT & Tt \\
\hline
t & Tt & tt \\
\hline
\end{array}
\][/tex]
For the second generation:
- The parents have genotypes Tt and Tt (heterozygous).
- The possible genotypes of the offspring are:
- TT (tall)
- Tt (tall)
- tt (short)
### Analyzing the Statements:
1. Plants with short stems are homozygous for that trait.
- Short stems are coded by the recessive allele (t). To express the short stem trait, the plant must have two recessive alleles (tt), meaning it must be homozygous recessive. This statement is true.
2. Plants with tall stems are always homozygous for that trait.
- Plants with tall stems can either be homozygous dominant (TT) or heterozygous (Tt). Hence, tall plants are not always homozygous. This statement is false.
3. Both parent plants in second generation are heterozygous.
- As observed from the second-generation Punnett square, the parent plants (Tt and Tt) both carry one dominant and one recessive allele, making them heterozygous. This statement is true.
4. Both parent plants in second generation are homozygous.
- As discussed, the parents (Tt and Tt) are heterozygous, not homozygous. This statement is false.
Based on our analysis, the correct statements are:
1. Plants with short stems are homozygous for that trait.
2. Both parent plants in second generation are heterozygous.
