In monocots vascular bundles are of closed types, what does it denote ?
(a) Xylem is surrounded by phloem
(b) Cambium is absent in vascular bundle
(c) The pores of vessel elements and sieve elements are closed
(d) No connection in between two successive internodes.

Options

A. Xylem is surrounded by phloem
B. Cambium is absent in vascular bundle
C. The pores of vessel elements and sieve elements are closed.
D. No connection in between two successive internodes.

Answer

To answer the question regarding what the closed type of vascular bundles in monocots denotes, we can analyze each option provided:

1. **Understanding Vascular Bundles**:
- Vascular bundles are composed of two main types of tissues: xylem and phloem.
- In monocots, these bundles are classified as "closed" types.

2. **Evaluating Each Option**:
- **Option (a)**: "Xylem is surrounded by phloem."
- This statement is not a defining characteristic of closed vascular bundles. The arrangement of xylem and phloem does not determine if the bundle is closed or open. Therefore, this option is **incorrect**.

- **Option (b)**: "Cambium is absent in vascular bundle."
- This is a defining feature of closed vascular bundles. In closed bundles, there is no cambium present between the xylem and phloem. This option is **correct**.

- **Option (c)**: "The pores of vessel elements and sieve elements are closed."
- The status of the pores does not define the type of vascular bundle. This statement is **incorrect**.

- **Option (d)**: "No connection in between two successive internodes."
- This statement does not relate to the classification of vascular bundles. The connection between internodes is not a defining feature of closed vascular bundles. Thus, this option is **incorrect**.

3. **Conclusion**:
- After evaluating all options, the correct answer is **(b) Cambium is absent in vascular bundle**. This is the characteristic that denotes closed vascular bundles in monocots.