Which of the following statement is incorrect ?

Options

A. A.Industrial melanism is an example of natural selection.
B. B.Before industrial revolution, Biston betularia with gray color was abundant .
C. C.Black - coloured form of the same moth ( melanic dominat mutant), carbonaria, increased after industrial revolution .
D. D.The gray colour of Biston betularis was due to dominant allele.

Answer

To determine which statement is incorrect, we will analyze each option provided in the question regarding industrial melanism and the peppered moth, Biston betularia.

### Step-by-Step Solution:

1. **Understanding Industrial Melanism**:
- Industrial melanism refers to the phenomenon where darker-colored individuals of a species become more common in polluted areas due to natural selection. This occurs as darker individuals are better camouflaged against predators in soot-darkened environments.

**Hint**: Remember that industrial melanism is a response to environmental changes, particularly pollution.

2. **Analyzing Option A**:
- Option A states that "industrial melanism is an example of natural selection." This is true because industrial melanism illustrates how environmental factors can influence the survival and reproduction of certain traits.

**Hint**: Consider how natural selection works in response to environmental pressures.

3. **Analyzing Option B**:
- Option B claims that "before the industrial revolution, Biston betularia with grey color was abundant." This is also true, as the grey coloration provided better camouflage in the unpolluted environment prior to industrialization.

**Hint**: Think about the historical context of the industrial revolution and its impact on species.

4. **Analyzing Option C**:
- Option C states that "the black colored moth, carbonaria, increased after the industrial revolution." This statement is true because the darker moths had a survival advantage in polluted areas where they were less visible to predators.

**Hint**: Reflect on how changes in the environment can lead to shifts in population dynamics.

5. **Analyzing Option D**:
- Option D claims that "the gray color of Biston betularia was due to a dominant allele." This statement is incorrect. The gray coloration is actually due to a recessive allele, while the black coloration (carbonaria) is due to a dominant allele.

**Hint**: Recall the basics of genetics regarding dominant and recessive alleles.

### Conclusion:
The incorrect statement among the options is **Option D**.