Two cross sections of stem and root appear simple, when viewed by naked eye. But under microscope they can be differentiated by
(a) Exarch condition of root and stem
(b) Endarch condition of stem and root
(c) Endarch condition of root and exarch condition of stem
(d) Endarch condition of stem and exarch condition of root

Options

A. Exarch condition of root and stem
B. Endarch condition of stem and root
C. Endarch condition of root and exarch condition of stem
D. Endarch condition of stem and exarch condition of root

Answer

To solve the question regarding the differentiation between the cross sections of stem and root under a microscope, we need to understand the terms "endarch" and "exarch" conditions in relation to the arrangement of xylem tissues.

### Step-by-Step Solution:

1. **Understanding the Terms**:
- **Endarch Condition**: In this condition, the protoxylem (the first-formed xylem) is located towards the center of the stem, while the metaxylem (the later-formed xylem) is located towards the periphery. This is typically observed in stems.
- **Exarch Condition**: In this condition, the protoxylem is located towards the periphery of the root, while the metaxylem is located towards the center. This is typically observed in roots.

2. **Identifying the Structures**:
- In stems, we expect to see an **endarch condition** where the protoxylem is centrally located.
- In roots, we expect to see an **exarch condition** where the protoxylem is located towards the outer layer.

3. **Analyzing the Options**:
- (a) Exarch condition of root and stem: Incorrect, as stems do not exhibit exarch conditions.
- (b) Endarch condition of stem and root: Incorrect, as roots do not exhibit endarch conditions.
- (c) Endarch condition of root and exarch condition of stem: Incorrect, as this is the opposite of the expected conditions.
- (d) Endarch condition of stem and exarch condition of root: Correct, as this matches our understanding.

4. **Conclusion**:
- The correct answer is **(d) Endarch condition of stem and exarch condition of root**. This option accurately describes the differences in xylem arrangement between stems and roots when viewed under a microscope.