Darwin proposed the theory of

Options

A. Inheritance of acquired characters
B. Natural selection
C. Recapitulation
D. Continuity of germplasm

Explanation

**Step-by-Step Solution:**

1. **Identify the Question:** The question asks about the theory proposed by Darwin.

2. **Evaluate the Options:**
- **Option 1:** Inheritance of acquired characters - This theory was proposed by Lamarck, not Darwin.
- **Option 2:** Natural selection - This is the theory proposed by Darwin.
- **Option 3:** Recapitulation - This theory was proposed by Ernst Haeckel.
- **Option 4:** Continuity of germplasm - This theory was proposed by August Weismann.

3. **Determine the Correct Answer:** Since the only theory listed that was proposed by Darwin is the theory of natural selection, this is the correct answer.

4. **Explain the Theory of Natural Selection:**
- Natural selection is a process where organisms that are better adapted to their environment tend to survive and produce more offspring.
- This leads to the concept of "survival of the fittest," where "fittest" refers to those best suited to their environment, not necessarily the strongest.

5. **Conclude the Answer:** The theory proposed by Darwin is the theory of natural selection.

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