If `F_(1)` generation has all tall plants and ratio of `F_(2)` generation is 3 tall : 1 dwarf, it proves

Options

A. Law of independent assortment
B. law of segregation
C. law of dominance
D. incomplete dominance

Answer

To solve the question, we need to analyze the information provided about the F1 and F2 generations of plants.

### Step-by-Step Solution:

1. **Understanding the F1 Generation**:
- The F1 generation consists of all tall plants. This indicates that the tall trait is dominant over the dwarf trait.
- If we denote the tall allele as "T" (dominant) and the dwarf allele as "t" (recessive), the genotype of the F1 plants must be heterozygous (Tt).

**Hint**: Remember that dominant traits mask the expression of recessive traits in heterozygous individuals.

2. **Crossing the F1 Generation**:
- When we self-cross the F1 plants (Tt x Tt), we can use a Punnett square to determine the genotypes of the F2 generation.
- The possible combinations from this cross will be:
- TT (homozygous tall)
- Tt (heterozygous tall)
- Tt (heterozygous tall)
- tt (homozygous dwarf)

3. **Determining the F2 Generation Ratio**:
- From the Punnett square, we can see that the genotypic ratio is:
- 1 TT : 2 Tt : 1 tt
- This translates to a phenotypic ratio of:
- 3 tall (TT and Tt) : 1 dwarf (tt)

**Hint**: Use a Punnett square to visualize the combinations of alleles from the parents.

4. **Interpreting the Results**:
- The observed ratio of 3 tall plants to 1 dwarf plant in the F2 generation supports two key principles of inheritance:
- **Law of Dominance**: The tall trait is dominant over the dwarf trait.
- **Law of Segregation**: During gamete formation, the alleles segregate so that each gamete carries only one allele for each gene.

5. **Conclusion**:
- The question specifically asks what the results prove. Since the F2 generation shows a 3:1 ratio, it primarily demonstrates the **Law of Segregation**, which states that alleles segregate independently during gamete formation.

**Final Answer**: The results prove the **Law of Segregation**.