Which one of the following cannot be explained on the basis of Mendel's Law of Dominance?

Options

A. (a) Factors occur in pairs
B. (b) The discrete unit controlling a particular character is called a factor
C. (c) Out of one pair of factor one is dominant, and the other is recessive.
D. (d) Alleles do not show any blending and both the characters recover as such in `F_(2)` generation

Answer

To solve the question "Which one of the following cannot be explained on the basis of Mendel's Law of Dominance?", we need to analyze each option in relation to Mendel's principles.

### Step-by-Step Solution:

1. **Understanding Mendel's Law of Dominance**:
Mendel's Law of Dominance states that in a heterozygous condition, the dominant allele will express its phenotype while the recessive allele will not show its effect unless in a homozygous condition.

**Hint**: Remember that dominant traits overshadow recessive traits in heterozygous individuals.

2. **Analyzing the Options**:
- **Option A**: "Factors occur in pairs."
- This is true as Mendel stated that genes (factors) come in pairs (alleles).
- **Option B**: "Discrete unit controlling a particular character."
- This is also true as the discrete units (alleles) control specific traits.
- **Option C**: "Out of one pair of factors, one is dominant and the other is recessive."
- This is a direct statement of the Law of Dominance and is true.
- **Option D**: "Alleles do not show any blending and both the characters recover as such in F2 generation."
- This statement refers to the Law of Segregation, which explains how alleles segregate independently during gamete formation and can reappear in the F2 generation.

3. **Identifying the Incorrect Explanation**:
- The only option that cannot be explained by Mendel's Law of Dominance is **Option D**. This is because it pertains to the Law of Segregation, which describes the separation of alleles during gamete formation and their independent assortment.

4. **Conclusion**:
- Therefore, the answer to the question is **Option D**.

### Final Answer:
**D**: Alleles do not show any blending and both the characters recover as such in F2 generation.