If dark skin colour is controlled by dominant genes MNO and its recessive allele is mno, what can be DEFINITELY said about the offsprings that are dark-skinned?

Options

A. They all have two copies of the dominant alleles.
B. They have at least one copy of the dominant allele.
C. They all have very high exposure to sunlight.
D. They do not have any exposure to sunlight.

Answer

To solve the question about the inheritance of dark skin color controlled by the dominant gene MNO, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Genes**:
- Dark skin color is controlled by the dominant allele MNO.
- The recessive allele is represented as mno.

2. **Identifying the Genotypes**:
- The possible genotypes for skin color are:
- Homozygous dominant: MNO MNO (dark-skinned)
- Heterozygous: MNO mno (dark-skinned)
- Homozygous recessive: mno mno (light-skinned)

3. **Analyzing Dark-Skinned Offspring**:
- If an offspring is dark-skinned, it can either have the genotype MNO MNO or MNO mno.
- This means that all dark-skinned offspring must have at least one dominant allele (MNO).

4. **Conclusion**:
- Therefore, we can definitely say that all dark-skinned offspring have at least one copy of the dominant allele (MNO).
- The correct statement regarding dark-skinned offspring is: "They have at least one copy of the dominant allele."

### Final Answer:
The offspring that are dark-skinned definitely have at least one copy of the dominant allele (MNO).

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