Observe the diagram and answer the following:
$(a)$ Identify the types of guard cells shown in $(i)$ and $(ii)$.
$(b)$ Which of these types is found in monocots and which in dicots?

(N/A) In the diagram,$(i)$ shows dumbbell-shaped guard cells,while $(ii)$ shows bean-shaped (or kidney-shaped) guard cells.
$(b)$ Dumbbell-shaped guard cells $(i)$ are characteristic of monocot plants (e.g.,grasses). Bean-shaped guard cells $(ii)$ are characteristic of dicot plants.