- A Open bundles have xylem facing outward; closed bundles have phloem facing outward instead
- B Open bundles have cambium (allow secondary growth); closed bundles have no cambium
- C Open bundles occur mainly in monocots; closed bundles occur mainly in dicots
- D Open bundles contain vessels; closed bundles contain mainly tracheids instead
Correct answer: B. Open bundles have cambium (allow secondary growth); closed bundles have no cambium
Explanation: Open vascular bundles contain cambium between xylem and phloem, allowing secondary (lateral) growth - found in dicot stems. Closed bundles have no cambium - found in monocot stems (no secondary growth).
Concept context
Internal tissue organisation: meristems, permanent tissues (xylem, phloem, parenchyma), and secondary growth. Frequently tested in NEET.