Which of the following is incorrect?

Options

A. Crossing over and Independent assortment are the two sources of genetic diversity in meiosis.
B. Meiosis and sexual reproduction have fostered diversity In natural world
C. Meiosis involves one replication only
D. Independent assortment occurs during metaphase II

Answer

To determine which statement is incorrect from the given options, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Understanding Genetic Variation**:
- The first statement suggests that genetic material will have variation if there is an exchange of genetic material. This is true because genetic recombination during processes like crossing over in meiosis leads to variation among offspring.

2. **Meiosis and Sexual Reproduction**:
- The second statement claims that meiosis and sexual reproduction have fostered diversity in natural birth. This is also correct, as meiosis produces haploid gametes that combine during fertilization, contributing to genetic diversity.

3. **DNA Replication in Meiosis**:
- The third statement mentions that meiosis involves only one replication of DNA. This is accurate; during meiosis, DNA is replicated once before the two rounds of division (meiosis I and meiosis II).

4. **Independent Assortment Timing**:
- The fourth statement states that independent assortment occurs during metaphase II. This is where the error lies. Independent assortment occurs during metaphase I of meiosis, where homologous chromosomes are aligned at the metaphase plate. During metaphase II, the sister chromatids are aligned, and the separation occurs in anaphase II.

### Conclusion:
The incorrect statement is the fourth one: "Independent assortment occurs during metaphase II."

### Final Answer:
The incorrect statement is: "Independent assortment occurs during metaphase II."

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