Question

A plant increases its thickness by
i. Apical meristem
ii. Vascular cambium
iii. Cork cambium
A. I
B. ii
C. iii
D. I and ii
E. ii and iii.

Answer 1

The growth of plants occurs in two ways, such as increasing in length that is apical growth, and the other one is increasing in the circumference or thickness and it is called as lateral growth of the plants, where the apical growth or increase in length or considered a primary growth and the growth in thickness is named as secondary growth.

Complete answer:

Apical meristem: Generally meristematic tissue Is bone which is undifferentiated tissue present in the plants where they grow and differentiate into various parts, and the meristematic tissue which was found in the apical regions of the plant tissues are called as apical meristems, and they helps in increasing the length of the plant, so it is the wrong answer.
Vascular cambium: In vascular plants, especially dicots, there is cambium which is present between the primary xylem and the primary phloem, and this is called intrafascicular cambium.
But during the secondary growth, the cells on medullary rays that line up and form the meristematic cells, which undergo differentiation and form the interfascicular vascular bundle.
Bothe these intra and interfascicular bundles combine to form a tube-like structure and they form vascular cambium, which forms secondary xylem inside the ring and secondary phloem outside the ring, moving the primary ones apart. So they are involved in the growth of plant thickness, so it is the correct option.
Cork cambium: cork cambium is also one of the types of cambium found in the vascular plants, where is one of the layers found between the cork that is bark and primary phloem, and this have lateral meristem, which makes the plant to grow in the thickness of the plant. So this is also one of the correct options.

So the correct option is E.

Note: Two types of meristematic tissues are found in the plants, which are apical and lateral meristematic tissue, which both are responsible for the growth of the plant, but apical meristem divides to increase the length of the plant, while lateral meristematic tissues help to increase thickness.