The longer the chromosomes of an organism, the more genetic variability it gets from .

Options

A. Independent assortment
B. Linkage
C. Crossing over
D. Mutation

Answer

### Step-by-Step Solution:

1. **Understanding Chromosome Length and Genetic Variability**:
- The question asks about the relationship between chromosome length and genetic variability. Longer chromosomes may provide more opportunities for genetic recombination during meiosis.

2. **Identifying the Process of Meiosis**:
- Meiosis is a type of cell division that reduces the chromosome number by half and is essential for sexual reproduction. It consists of two rounds of division: meiosis I and meiosis II.

3. **Crossing Over in Meiosis**:
- During prophase I of meiosis, homologous chromosomes pair up to form a structure called a bivalent or tetrad. This is where crossing over occurs, which involves the exchange of genetic material between non-sister chromatids.

4. **Impact of Crossing Over on Genetic Variability**:
- The exchange of genetic material during crossing over increases genetic variability in the offspring. The more extensive the chromosome length, the greater the potential for crossing over to occur, leading to more genetic combinations.

5. **Evaluating Other Options**:
- The other options provided (independent assortment, linkage, and mutation) do not directly relate to chromosome length affecting genetic variability:
- **Independent Assortment**: This principle states that genes for different traits assort independently of one another, but it does not relate to chromosome length.
- **Linkage**: This refers to genes located close together on the same chromosome, which reduces variability due to less recombination.
- **Mutation**: While mutations can introduce variability, they are not influenced by chromosome length.

6. **Conclusion**:
- The correct answer to the question is option C, as the length of chromosomes allows for more crossing over during meiosis, which increases genetic variability.