Law of dominance-recessiveness is proved by:

Options

A. Back cross
B. Incomplete dominance
C. Monohybrid cross
D. Dihybrid cross

Answer

**Step-by-Step Solution:**

1. **Understanding the Law of Dominance-Recessiveness**: The Law of Dominance states that in a heterozygote, one allele may conceal the presence of another allele. This means that the dominant trait will be expressed while the recessive trait will not be observed in the phenotype.

2. **Identifying the Methods to Prove the Law**: The law can be demonstrated through various genetic crosses, including:
- Back Cross
- Incomplete Dominance
- Monohybrid Cross
- Dihybrid Cross

3. **Analyzing Each Option**:
- **Back Cross**: This involves crossing the F1 progeny with one of the parental types. While it can show dominance, it is not a direct proof of the law itself.
- **Incomplete Dominance**: This occurs when neither allele is completely dominant, resulting in a blending of traits. This does not support the law of dominance-recessiveness, as both alleles contribute to the phenotype.
- **Monohybrid Cross**: This is a cross between two organisms that differ in one trait. For example, crossing a homozygous dominant (AA) with a homozygous recessive (aa) will yield offspring (F1) that are all heterozygous (Aa), demonstrating the dominance of the dominant allele.
- **Dihybrid Cross**: This involves two traits and shows the law of independent assortment rather than dominance-recessiveness.

4. **Conclusion**: The Law of Dominance-Recessiveness is best proved by the Monohybrid Cross, where the dominance of one allele over another can be clearly observed.

**Final Answer**: The Law of Dominance-Recessiveness is proved by the Monohybrid Cross.

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