How many cleavages are required for formation of 16 blastomeres .

Options

A. 2
B. 4
C. 6
D. 8

Answer

To determine how many cleavages are required to form 16 blastomeres, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Cleavage**:
- Cleavage is the process by which a single fertilized egg (zygote) divides into multiple cells called blastomeres. Each cleavage results in the doubling of the number of blastomeres.

2. **Counting Blastomeres**:
- After the first cleavage, the zygote divides into 2 blastomeres.
- After the second cleavage, the number of blastomeres becomes 4 (2^2).
- After the third cleavage, the number of blastomeres becomes 8 (2^3).
- After the fourth cleavage, the number of blastomeres becomes 16 (2^4).

3. **Identifying the Pattern**:
- The pattern shows that the number of blastomeres can be expressed as 2^n, where n is the number of cleavages.
- To find the number of cleavages needed to reach 16 blastomeres, we set up the equation:
\[ 2^n = 16 \]

4. **Solving for n**:
- We know that 16 can be expressed as 2 raised to the power of 4:
\[ 2^4 = 16 \]
- Thus, n = 4.

5. **Conclusion**:
- Therefore, 4 cleavages are required to form 16 blastomeres.

### Final Answer:
4 cleavages are required for the formation of 16 blastomeres.

---