Question

A narrow layer of thin-walled cells found between phloem/ bark and wood of a dicot is?
A) Cork cambium
B) Vascular cambium
C) Endodermis
D) Pericycle

Answer 1

Hint: In plants, there is vascular tissue found called xylem and the phloem, which are helpful for the conduction of water and nutrients, and in between this tissues some layer of cells are present which results in the secondary growth of the plants, and secondary growth is commonly seen in dicots and absent in monocots.

Complete answer:
In plants, especially in dicot plants some layer of meristematic cells are present which are helpful for the formation of thickness of the plants, and this meristems are also called lateral meristems, in plants meristems are majorly of two types that are apical meristem which helps to grow length, and other is lateral meristem.
In between the primary xylem and primary phloem a thin layer of cells are present which are called as intrafascicular cambium and this is present as beads in the stems of dicots.
At the same time the thin line of cells medullary rays are lined up which are also meristematic, that are present between vascular bundles and they are called as Interfascicular cambium.
The both interfascicular and interfascicular cambium get together joined and form the tube like structure which we called it as vascular cambium, and this vascular cambium divides and form the secondary growth where they form both secondary xylem and secondary phloem.
It forms the secondary xylem towards the inside of the ring and the secondary phloem from the outside of the ring, and it moves the primary Xylem and Phloem apart from the circle of the ring.

So, the correct option is B.

Note: To explain in simple way, the layer of cells that are found between the Phloem and bark are called as vascular cambium, and this is formed by both intra and interfascicular cells, where they are meristematic, so they divide and form the secondary xylem and Phloem.