The endarch condition is characteristic of
(a) root
(b) stem
(c) leaves
(d) petiole

Options

A. root
B. stem
C. leaves
D. petiole

Answer

To solve the question regarding the endarch condition, we will analyze each option step by step.

### Step 1: Understanding the Endarch Condition
The endarch condition refers to the arrangement of xylem in which the protoxylem is located towards the center (medulla) and the metaxylem is located towards the outside (pericycle). This is a specific characteristic of certain plant structures.

**Hint:** Remember the arrangement of protoxylem and metaxylem in relation to the center and outside of the plant part.

### Step 2: Analyzing the Root
In roots, the arrangement of xylem is different. The protoxylem is located towards the pericycle (outer layer), while the metaxylem is towards the center (medulla). This arrangement is known as the exarch condition.

**Hint:** Consider how xylem is arranged in roots compared to the definition of endarch.

### Step 3: Analyzing the Stem
In stems, the arrangement is the opposite of that in roots. Here, the protoxylem is located towards the center (medulla), and the metaxylem is towards the outside (pericycle). This arrangement is characteristic of the endarch condition.

**Hint:** Focus on the arrangement of xylem in stems and how it fits the definition of endarch.

### Step 4: Analyzing Leaves and Petiole
Leaves and petioles do not have a specific arrangement of protoxylem and metaxylem that fits the endarch condition. They typically have a different vascular structure that does not conform to the definitions of either endarch or exarch.

**Hint:** Think about whether leaves and petioles have the same xylem arrangement as stems or roots.

### Conclusion
Based on the analysis:
- Roots exhibit exarch condition.
- Stems exhibit endarch condition.
- Leaves and petioles do not specifically exhibit either condition.

Thus, the correct answer is **(b) stem**.

**Final Answer:** (b) stem