Study the four statements given below and answer the question which follow them. I) Inbreeding is necessary if we want to develop a pureline in animals II) inbreeding exposes harmful recessive genes that are eliminated by selection III) continuous inbreeding usually reduces fertility and productivity IV) inbreeding depression can be overcome by outcrossing How many of the above statements are correct?

Options

A. Two
B. Three
C. Four
D. One

Answer

To determine how many of the four statements about inbreeding are correct, let's analyze each statement step by step.

### Step 1: Analyze Statement I
**Statement I:** Inbreeding is necessary if we want to develop a pure line in animals.
- **Analysis:** This statement is correct. Inbreeding is indeed used to develop pure lines in animals as it promotes homozygosity, which is essential for establishing a pure breed.

### Step 2: Analyze Statement II
**Statement II:** Inbreeding exposes harmful recessive genes that are eliminated by selection.
- **Analysis:** This statement is also correct. Inbreeding can reveal harmful recessive alleles that may not be expressed in heterozygous individuals. Once these harmful genes are exposed, they can be selected against, leading to their elimination from the population.

### Step 3: Analyze Statement III
**Statement III:** Continuous inbreeding usually reduces fertility and productivity.
- **Analysis:** This statement is correct as well. Continuous inbreeding can lead to inbreeding depression, which is characterized by reduced fertility, vitality, and overall productivity of the animals.

### Step 4: Analyze Statement IV
**Statement IV:** Inbreeding depression can be overcome by outcrossing.
- **Analysis:** This statement is correct. Outcrossing, which involves breeding individuals from different genetic backgrounds, can help restore vigor and counteract the negative effects of inbreeding depression.

### Conclusion
All four statements are correct. Therefore, the answer to the question is that **all four statements are correct**.

### Final Answer
**All four statements are correct.**

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