Both animal and plant cells have a well defined cell wall.
A. True
B. False

Answer

To determine whether the statement "Both animal and plant cells have a well-defined cell wall" is true or false, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Cell Walls**:
- A cell wall is a rigid structure that surrounds the cell membrane, providing support and protection to the cell.

2. **Identifying Cell Wall Presence in Plant Cells**:
- Plant cells possess a well-defined cell wall. This cell wall is primarily made up of cellulose, a complex polysaccharide. It serves various functions including protection and maintaining cell shape.

3. **Identifying Cell Wall Presence in Animal Cells**:
- In contrast, animal cells do not have a cell wall. Instead, they are surrounded by a flexible plasma membrane. The absence of a cell wall allows for a greater range of motion and flexibility in animal cells.

4. **Conclusion**:
- Since only plant cells have a well-defined cell wall and animal cells do not, the statement "Both animal and plant cells have a well-defined cell wall" is false.

5. **Final Answer**:
- The correct option is B. False.