To determine the probability of obtaining a short, homozygous pea plant (tt) from a cross between two tall, heterozygous pea plants (Tt), we can use a Punnett square.
1. Set up the Punnett square with the gametes from each parent:
- One parent (Tt) can produce gametes: T and t
- The other parent (Tt) can also produce gametes: T and t
The Punnett square looks like this:
```
T t
______________
T | TT | Tt |
|__________|_______|
t | Tt | tt |
|__________|_______|
```
2. Now, let's analyze the possible genotypes of the offspring:
- **TT**: 1 square
- **Tt**: 2 squares
- **tt**: 1 square
3. From this, the genotypic ratio of the offspring is:
- TT: 1
- Tt: 2
- tt: 1
4. The probability of the offspring being short and homozygous (tt) is:
- There is 1 tt out of a total of 4 possible genotypes.
Thus, the probability is \( \frac{1}{4} = 25\% \).
So the correct response is:
**25%**