Identify the parts labeled $(a)$,$(b)$,and $(c)$ in the given diagram and state one function for each.

(N/A) Lateral meristem: It is responsible for the increase in the girth (thickness) of the stem and root.
$(b)$ Intercalary meristem: It is responsible for the growth of internodes and the formation of leaves and branches.
$(c)$ Apical meristem: It is responsible for the increase in the length of the stem and the root.