In a cross between plants with purple flowers and plants with white flowers, the offspring of `F_1` generation all had white flowers. When the `F_1` generation was self-crossed, it was observed in the `F_2` generation that out of 100, 75 flowers were white. Make a cross and answer the following questions:
In a monohybrid cross between two heterozygous individuals, percentage of pure homozygous individuals obtained in `F_1` generation is?

Options

A. 0.25
B. 0.5
C. 0.75
D. 1

Explanation

To solve the problem, we need to understand the genetics behind the flower color in the plants mentioned. Here’s a step-by-step breakdown of the solution:

### Step 1: Identify the Traits
In the given scenario, we have two traits:
- **Purple flowers** (recessive trait) represented by **ww**
- **White flowers** (dominant trait) represented by **WW** or **Ww**

### Step 2: Determine the F1 Generation
When we cross a plant with purple flowers (ww) with a plant with white flowers (WW), all the offspring (F1 generation) will have the genotype **Ww** (heterozygous) because the white flower trait is dominant. Therefore, all F1 plants will have white flowers.

### Step 3: Self-Cross the F1 Generation
Now, we self-cross the F1 generation (Ww x Ww). We can use a Punnett square to determine the genotypes of the F2 generation.

### Step 4: Create the Punnett Square
1. Write the gametes from each parent:
- Parent 1 (Ww): Gametes = W, w
- Parent 2 (Ww): Gametes = W, w

2. Set up the Punnett square:
```
W w
----------------
W | WW | Ww |
----------------
w | Ww | ww |
----------------
```

### Step 5: Analyze the Results
From the Punnett square, we can see the following genotypes:
- **WW** (homozygous dominant): 1
- **Ww** (heterozygous): 2
- **ww** (homozygous recessive): 1

### Step 6: Calculate the Percentages
- Total offspring = 4 (1 WW + 2 Ww + 1 ww)
- Pure homozygous individuals (WW and ww) = 1 (WW) + 1 (ww) = 2
- Percentage of pure homozygous individuals = (Number of homozygous individuals / Total offspring) × 100
- Percentage = (2 / 4) × 100 = 50%

### Final Answer
The percentage of pure homozygous individuals obtained in the F1 generation is **50%**.

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