Which of these was most influential in formulation of Natural selection Theory by Darwin?

Options

A. Malthus essay on population
B. Inheritance of acquired characters
C. Mendelian laws of inheritance
D. Struggle for existence

Answer

To determine which factor was most influential in the formulation of Darwin's theory of natural selection, we can analyze the provided options step by step.

### Step-by-Step Solution:

1. **Understanding the Options**:
- We have four options to consider:
1. Malthus's essay on population
2. Inheritance of acquired characters
3. Mendelian laws of inheritance
4. Struggle for existence

2. **Evaluating Malthus's Essay on Population**:
- Thomas Malthus wrote about how populations grow exponentially while resources grow arithmetically. This concept highlights the struggle for resources, which is a key component of natural selection. Darwin used this idea to explain how organisms compete for limited resources, leading to survival of the fittest.
- **Conclusion**: This option is influential in the formulation of natural selection theory.

3. **Evaluating Inheritance of Acquired Characters**:
- This concept, proposed by Lamarck, suggests that traits acquired during an organism's lifetime can be passed to offspring. However, this idea does not align with Darwin's theory, which is based on genetic inheritance rather than acquired traits.
- **Conclusion**: This option is not influential in the formulation of natural selection theory.

4. **Evaluating Mendelian Laws of Inheritance**:
- Gregor Mendel's work on inheritance was not known to Darwin during his formulation of the natural selection theory. Mendel's principles of heredity were published after Darwin's work, and thus did not influence Darwin's ideas directly.
- **Conclusion**: This option is not influential in the formulation of natural selection theory.

5. **Evaluating Struggle for Existence**:
- While the struggle for existence is a concept related to natural selection, it is not a standalone theory or influential factor in the same way that Malthus's essay is. It is more of a consequence of the ideas presented by Malthus.
- **Conclusion**: This option is not directly influential in the formulation of natural selection theory.

6. **Final Conclusion**:
- Based on the analysis, the most influential factor in the formulation of Darwin's theory of natural selection is **Malthus's essay on population**.

### Answer:
The correct answer is **Malthus's essay on population**.

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