Regarding fertilization which among the following statement is incorrect?

Options

A. It restores diploid condition in the zygote
B. Paternal and maternal sets contribute to the diploid number without causing any variation
C. it activates egg both physiologically and metabolically
D. It determines the sex of the offspring

Answer

To determine which statement regarding fertilization is incorrect, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding Fertilization**:
- Fertilization is defined as the fusion of male and female gametes, resulting in the formation of a zygote. This process restores the diploid condition in the organism.

**Hint**: Remember that fertilization involves the combination of genetic material from both parents.

2. **Analyzing Option 1**:
- Option 1 states that fertilization restores the diploid condition in the zygote. This statement is correct because the zygote formed after fertilization contains two sets of chromosomes (one from each parent), thus restoring the diploid state.

**Hint**: Consider what happens to the chromosome number during fertilization.

3. **Analyzing Option 2**:
- Option 2 claims that paternal and maternal sets contribute to the diploid number without causing any variation. This statement is incorrect. While fertilization does restore the diploid number, it inherently involves genetic variation due to the combination of different alleles from each parent.

**Hint**: Think about how genetic variation occurs during sexual reproduction.

4. **Analyzing Option 3**:
- Option 3 states that fertilization activates both physiologically and metabolically. This statement is correct as fertilization triggers various biological processes that lead to the development of the zygote.

**Hint**: Consider the changes that occur in the cell after fertilization.

5. **Analyzing Option 4**:
- Option 4 mentions that fertilization determines the sex of the offspring. This statement is also correct. The sex of the offspring is determined by the combination of sex chromosomes (XX for female and XY for male).

**Hint**: Recall how sex chromosomes contribute to the determination of sex in offspring.

### Conclusion:
After analyzing all options, the incorrect statement regarding fertilization is **Option 2**, which suggests that the contribution of paternal and maternal sets does not cause any variation.

### Final Answer:
**Option 2 is the incorrect statement.**