According to the evolutionary theory, formation of a nes species is generally due to.

Options

A. sudden creation by nature
B. accumulation of variations over several generations
C. clones formed during asexual reproduction
D. movement of individuals from one habitat to another

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the formation of new species according to evolutionary theory. We need to identify the main factors that contribute to this process.

2. **Key Concept of Evolutionary Theory**: Evolutionary theory states that new species arise due to changes in the genetic material of organisms. These changes can occur through mutations or variations.

3. **Accumulation of Variations**: Over time, as variations in genetic material accumulate, they can lead to significant changes in the organism. If these variations are beneficial for survival, they will be favored by natural selection.

4. **Generational Impact**: The beneficial variations that enhance survival will be passed on to the next generation. This process continues over many generations, leading to the evolution of a new species.

5. **Evaluating the Options**:
- **Option A**: Sudden creation by nature - This is incorrect as evolutionary changes are gradual, not sudden.
- **Option B**: Accumulation of variation over several generations - This is correct as it aligns with the principles of evolutionary theory.
- **Option C**: Clones formed during asexual reproduction - This is incorrect because clones do not introduce genetic variation necessary for new species formation.
- **Option D**: Movement of individuals from one habitat to another - This may cause some genetic changes but is not a primary factor in the formation of new species.

6. **Conclusion**: The correct answer is **Option B**, which states that the formation of a new species is generally due to the accumulation of variation over several generations.