Asexual reproduction is common among all except:

Options

A. unicellular organisms
B. Plants with simple organization
C. Animals with simple organization
D. Animals with complex organization

Answer

To solve the question "Asexual reproduction is common among all except:", we need to analyze the options provided and understand the characteristics of asexual reproduction.

### Step-by-Step Solution:

1. **Understanding Asexual Reproduction**:
- Asexual reproduction is a mode of reproduction that does not involve the fusion of gametes (sperm and egg). It typically involves a single parent organism producing offspring that are genetically identical to itself.

2. **Identifying Organisms That Reproduce Asexually**:
- Asexual reproduction is common in unicellular organisms (like bacteria and protozoa), some plants (like ferns and certain flowering plants), and some simple multicellular organisms (like sponges and hydra).

3. **Considering Complex Organisms**:
- In contrast, complex organisms, particularly many animals with advanced body structures and systems (like mammals, birds, and reptiles), generally do not reproduce asexually. They rely on sexual reproduction, which involves two parents and the combination of genetic material.

4. **Evaluating the Options**:
- If the options include unicellular organisms, simple plants, and complex animals, we can conclude that complex animals are the exception where asexual reproduction is not common.

5. **Conclusion**:
- Therefore, the correct answer to the question is that asexual reproduction is common among all except complex animals.

### Final Answer:
- Asexual reproduction is common among all except complex animals.