To solve the problem, we need to analyze the genetic makeup of the corn plants based on the information provided.
### Step-by-Step Solution:
1. **Understand the Phenotypes and Genotypes**:
- The problem states that from 200 kernels, 140 plants are tall and 40 plants are dwarf.
- Tall plants can be either homozygous dominant (TT) or heterozygous (Tt), while dwarf plants are homozygous recessive (tt).
2. **Determine the Ratio of Tall to Dwarf Plants**:
- The total number of plants is 200.
- The ratio of tall to dwarf plants is 140:40, which simplifies to 7:2.
3. **Use the Expected Ratios in Mendelian Genetics**:
- In a typical monohybrid cross involving a dominant trait (tall) and a recessive trait (dwarf), the expected phenotypic ratio is 3:1 for dominant to recessive traits.
- However, in this case, we have a 7:2 ratio, which suggests that there are heterozygous plants present.
4. **Calculate the Number of Heterozygous Plants**:
- If we denote the number of homozygous tall plants as "TT", the number of heterozygous plants as "Tt", and the number of homozygous dwarf plants as "tt", we can set up the following equations:
- TT + Tt + tt = 200 (total plants)
- TT + Tt = 140 (tall plants)
- tt = 40 (dwarf plants)
- From the dwarf plants, we know tt = 40. Therefore, TT + Tt = 200 - 40 = 160.
5. **Set Up the Equations**:
- Now we have two equations:
- TT + Tt = 160 (1)
- TT + Tt = 140 (2)
- From equation (1) and (2), we can deduce that:
- Tt = 20 (since 160 - 140 = 20).
6. **Determine the Genotypes**:
- Therefore, we can conclude:
- TT (homozygous tall) + Tt (heterozygous) = 140
- tt (homozygous dwarf) = 40
- Tt (heterozygous) = 20
- This gives us the genotypes as follows:
- Homozygous tall (TT) + Heterozygous (Tt) + Homozygous dwarf (tt).
7. **Final Genotype Representation**:
- The genotypes of the offspring are most likely:
- TT (homozygous tall), Tt (heterozygous), and tt (homozygous dwarf).
### Conclusion:
The correct genotype representation based on the given information is:
- **Option A: TT, Tt, and tt**.
