The phenomenon that is not part of Darwin's theory was :

Options

A. Survival of the fittest
B. Arrival to the fittest
C. Branching descent
D. Struggle for existence

Answer

To solve the question regarding which phenomenon is not part of Darwin's theory, we can follow these steps:

**Step 1: Understand Darwin's Theory of Evolution**
- Darwin's theory primarily revolves around natural selection, which includes concepts such as "survival of the fittest," "struggle for existence," and "branching descent."

**Step 2: Analyze the Options Given**
- A. Survival of the fittest: This is a key component of Darwin's theory, referring to the idea that individuals best adapted to their environment are more likely to survive and reproduce.
- B. Arrival of the fittest: This phrase is not part of Darwin's theory. It suggests that the fittest individuals arrive or come into existence, which is not aligned with the principles of natural selection.
- C. Branching descent: This concept refers to the idea that species evolve from common ancestors, which is indeed part of Darwin's theory.
- D. Struggle for existence: This concept is also part of Darwin's theory, emphasizing the competition among organisms for resources.

**Step 3: Identify the Correct Answer**
- Based on the analysis, the phenomenon that is not part of Darwin's theory is "B. Arrival of the fittest."

**Final Answer:**
- The correct answer is **B. Arrival of the fittest.**

---