If 120 Planta are produced on crossing pure red and pure white flowered pea plants, than the ratio of offsprings will be:-

Options

A. 90 Red : 30 White
B. 30 Red : 90 White
C. 60 Red : 60 White
D. All Red

Answer

To solve the problem of determining the ratio of offspring produced by crossing pure red and pure white flowered pea plants, we can follow these steps:

### Step-by-step Solution:

1. **Identify the Genotypes of the Parent Plants**:
- The genotype of the pure red flowered pea plant is **RR** (homozygous dominant).
- The genotype of the pure white flowered pea plant is **rr** (homozygous recessive).

2. **Determine the F1 Generation**:
- When we cross the two parent plants (RR x rr), all offspring in the F1 generation will have the genotype **Rr**.
- Since the allele for red flowers (R) is dominant over the allele for white flowers (r), all F1 plants will express the red flower phenotype.

3. **Calculate the Number of Offspring**:
- According to the problem, a total of **120 plants** are produced from this cross.

4. **Determine the Phenotypic Ratio**:
- Since all F1 plants are red flowered (Rr), the phenotypic ratio of the offspring will be:
- **Red flowers : White flowers = 120 : 0**.
- This means all 120 plants are red, and there are no white flowered plants.

5. **Conclusion**:
- Therefore, the ratio of offspring will be **all red**.

### Final Answer:
The ratio of offspring will be **all red**.

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