Answer:
Cuticle - It also has a waxy material that protects the leaf from attacks by bacteria, protects inner tissues from mechanical damage and acts as a water proof layer to prevent excessive water loss.
Palisade mesophyll - They have many chloroplasts used to absorb light energy used for photosynthesis.
Spongy mesophyll - The cells are loosely packed together leaving air spaces that allow for air circulation and gaseous exchange.
Guard cell - They have thick inner walls and thin outer walls to control the opening and closing of the stomata.