The cells that multiply and produce growth at various parts of a plant are called meristematic cells.

Here's why:

* Meristematic cells are undifferentiated cells with the ability to divide and differentiate into specialized cells.

* They are responsible for primary growth, which increases the length of the plant (roots and shoots), and secondary growth, which increases the width of the plant (woody stems and roots).

* Apical meristems are found at the tips of roots and shoots, responsible for primary growth.

* Lateral meristems are found in the cambium layer, responsible for secondary growth.

So, whenever you see a plant growing taller, wider, or developing new roots, you can think of meristematic cells hard at work!