The two types of ribosomes are

Options

A. `{:("Nucleus","cytoplasm"),("Free","fixed"):}`
B. `{:("Endoplasmic reticulum","Nucleus"),("fixed","Free"):}`
C. `{:("Endoplasmic reticulum","Nucleus"),("Free","fixed"):}`
D. `{:("cytoplasm","Nucleus"),("fixed","Free"):}`

Answer

### Step-by-Step Solution:

1. **Understanding Ribosomes**: Ribosomes are essential cell organelles known as the "protein factories" of the cell because they are responsible for synthesizing proteins.

2. **Types of Ribosomes**: There are two main types of ribosomes found in cells:
- **Fixed Ribosomes**: These ribosomes are attached to the surface of the endoplasmic reticulum (ER). When ribosomes are attached to the ER, it is referred to as Rough Endoplasmic Reticulum (RER).
- **Free Ribosomes**: These ribosomes float freely in the cytosol of the cell and are not attached to any organelle.

3. **Location of Ribosomes**:
- **Fixed Ribosomes**: Found on the Rough Endoplasmic Reticulum (RER).
- **Free Ribosomes**: Found in the cytosol of the cell.

4. **Conclusion**: The two types of ribosomes are:
- Fixed Ribosomes (on the Rough Endoplasmic Reticulum)
- Free Ribosomes (in the cytosol)