Rhizoids differ from roots as

Options

A. rhizoids are always unicellular but roots are multicellular
B. rhizoids arise in gametophytes but roots in sporophytes
C. roots are branched but rhizoids are always unbranched.
D. all of the above.

Answer

To answer the question "Rhizoids differ from roots as," we need to analyze the options provided and understand the characteristics of rhizoids and roots.

### Step-by-Step Solution:

1. **Understanding Rhizoids**:
- Rhizoids are structures found in bryophytes (like mosses and liverworts).
- They primarily serve to anchor the plant to the substrate (soil or rock).
- Rhizoids can be unicellular or multicellular, but they are typically simpler in structure compared to roots.

2. **Understanding Roots**:
- Roots are found in more complex plants (like angiosperms and gymnosperms).
- They are part of the sporophyte generation, which is diploid.
- Roots are responsible for anchoring the plant and absorbing water and nutrients from the soil.

3. **Analyzing the Options**:
- **Option 1**: "Rhizoids are always unicellular but roots are multicellular."
- This statement is partially incorrect because rhizoids can be multicellular as well.
- **Option 2**: "Rhizoids arise in gametophyte but roots in sporophyte."
- This statement is correct. Rhizoids are associated with the gametophyte stage, while roots are part of the sporophyte stage.
- **Option 3**: "Roots are branched but rhizoids are always unbranched."
- This statement is misleading. While roots are typically branched, rhizoids can also be branched depending on the species.
- **Option 4**: "All of the above."
- Since options 1 and 3 are not entirely correct, this option cannot be true.

4. **Conclusion**:
- The correct answer is **Option 2**: "Rhizoids arise in gametophyte but roots in sporophyte."