Question

In a plant shoot, growth in length is due to cell division in the
A. Vascular cambium
B. Apical meristem
C. Cortex
D. Cork cambium

Answer 1

In plants, growth occurs in the form of primary and secondary growth. Primary growth is mainly responsible for the elongation of stems and roots which occurs due to the presence of rapidly dividing cells while the secondary growth is mainly responsible for increasing the thickness or girth of the plants.

Complete answer:
Option (A) is incorrect. Vascular cambium is present in between the primary xylem and phloem of the stems and roots of vascular plants and is known for the formation of secondary xylem and phloem. It helps in increasing the diameter or thickness of stems and roots and also forms the tissue of woody plants.
Option (B) is correct. Apical meristem is present at the tips of shoots and roots of the plant and they possess rapidly dividing cells that divide throughout their life and help in the lengthening of shoots and roots of the plants.

Option (C) is incorrect. Cortex is a tissue made up of unspecialized cells that is present in between the epidermis and vascular tissues of stems and roots. It is meant for the storage of food in the form of starch.
Option (D) is incorrect. Cork cambium is a lateral meristem that is known for secondary growth in plants and is known to form the cork.

Hence, the correct option is (B).

Note: Primary growth in plants i.e., elongation of shoots and roots mostly occurs at the tips of the shoots and roots due to the presence of apical meristems at the tips. Secondary growth i.e., increasing the diameter of the shoots and roots mostly takes place due to the presence of lateral meristems such as vascular cambium and cork cambium.