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 determine which group does not primarily reproduce asexually.

### Step-by-Step Solution:

1. **Understand Asexual Reproduction**:
- Asexual reproduction is a mode of reproduction where a new organism is formed from a single parent without the involvement of gametes (sperm and egg). The offspring are genetically identical to the parent.

2. **Evaluate the Options**:
- **Option 1: Unicellular organisms**:
- Unicellular organisms, such as bacteria and amoebae, commonly reproduce asexually through processes like binary fission. Therefore, this option is not the correct answer.

- **Option 2: Plants with simple organization**:
- Many simple plants, such as algae and mosses, can reproduce asexually through methods like fragmentation, budding, or spore formation. This option is also not the correct answer.

- **Option 3: Animals with simple organization**:
- Simple animals, such as hydra and planaria, can reproduce asexually through processes like budding and regeneration. Thus, this option is not the correct answer either.

- **Option 4: Animals with complex organization**:
- Animals with complex organization, such as mammals and birds, primarily reproduce sexually. While some complex animals may have asexual reproduction capabilities (like certain species of lizards), it is not the common mode of reproduction for the majority of complex organisms.

3. **Conclusion**:
- Based on the analysis of the options, the correct answer is **Option 4: Animals with complex organization**, as they do not commonly reproduce asexually.

### Final Answer:
Asexual reproduction is common among all except: **Animals with complex organization**.