Type of natural selection that eliminates deleterious variants and keeps the species unchanged is

Options

A. Directional selection
B. Stabilising selection
C. Disruptive selection
D. Diversifying selection

Answer

To answer the question regarding the type of natural selection that eliminates deleterious variants while keeping the species unchanged, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Natural Selection**: Natural selection is a process where organisms better adapted to their environment tend to survive and produce more offspring. There are different types of natural selection, including directional, stabilizing, disruptive, and diversifying selection.

2. **Identify the Key Terms**: The question specifies "eliminates deleterious variants" and "keeps the species unchanged." This implies that we are looking for a type of selection that maintains the average traits of a population while filtering out harmful variations.

3. **Analyze the Options**:
- **Directional Selection**: This type favors one extreme phenotype over others, leading to a shift in the population's traits. It does not keep the species unchanged.
- **Stabilizing Selection**: This selection favors the average phenotype and reduces variation. It eliminates extreme traits, thus maintaining the status quo of the species.
- **Disruptive Selection**: This type favors extreme phenotypes at both ends of the spectrum, which can lead to a split in the population and changes in the species.
- **Diversifying Selection**: Similar to disruptive selection, it favors multiple extreme traits over the average, leading to changes in the species.

4. **Select the Correct Answer**: Based on the analysis, **stabilizing selection** is the type that eliminates deleterious variants while keeping the species unchanged. It focuses on maintaining the average traits and reducing extremes.

5. **Conclusion**: Therefore, the correct answer to the question is **stabilizing selection**.

### Final Answer:
**Stabilizing Selection (Option B)**

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