Study the given situation.
Plants that beetles feed upon suffered from a disease and died. Due to reduced food, beetles are poorly nourished and show reduced weight. But there is no genetic change. After few years plant disease is eliminated. Now abundance of leaf food causes weight gain in next beetle generations.
Which of the following statements best explains the given situation?

Options

A. Natural selection is the phenomenon where nature selects organism having traits favourable to the environment.
B. Acquired trait does not bring any change in the DNA and therefore this trait is not inherited.
C. Speciation leads to the formation of species due to reproductive isolation.
D. Genetic drift leads to elimination of genes of certain traits from a small population when a section of the species population dies of natural calamity.

Answer

To solve the question, we need to analyze the situation presented and identify which statement best explains the changes observed in the beetle population over time.

### Step-by-Step Solution:

1. **Understanding the Initial Situation**:
- The plants that beetles feed on suffered from a disease and died. This led to a reduced food supply for the beetles.
- As a consequence of the lack of food, the beetles became poorly nourished and showed reduced weight.

2. **Observation of Generational Change**:
- The first generation of beetles was negatively affected due to the lack of food, resulting in poor health and reduced weight.
- After a few years, the plant disease was eliminated, leading to an abundance of leaf food.

3. **Impact on Subsequent Generations**:
- With the return of abundant food, the next generations of beetles experienced weight gain and improved health.
- It is important to note that there was no genetic change in the beetles during this time.

4. **Evaluating the Statements**:
- **Option 1**: Refers to natural selection. This is not applicable here since the beetles did not evolve or adapt genetically during the food shortage.
- **Option 2**: States that acquired traits do not bring any change in DNA and therefore are not inherited. This aligns with the situation, as the first generation's poor health did not affect the genetic makeup of the subsequent generations.
- **Option 3**: Discusses speciation, which is not relevant to the situation described.
- **Option 4**: Talks about genetic drift, which also does not apply since the beetles did not lose genetic traits but rather experienced a temporary change in health due to environmental factors.

5. **Conclusion**:
- The best explanation for the situation is that acquired traits (such as reduced weight due to poor nourishment) do not affect the DNA and are not inherited by the next generation. Therefore, the correct answer is **Option 2**.