Answer:
Diffusion helps animals in respiration. The cells in an animal's body need glucose and oxygen for respiration. Both these are carried in the blood. When blood reaches the cells the molecules of glucose and oxygen diffuse out of the blood and into the cells. As cells use up the glucose and oxygen they produce waste chemicals and carbon dioxide.
Diffusion is a very important process for photosynthesis where carbon dioxide from the stomata diffuses into the leaves and finally into the cells. This helps the plants to photosynthesize and produce more food.
Example for animals: Animals using glucose and oxygen in diffusion.
Examples for plants: Plants using carbon dioxide to photosynthesize.
The desert and tundra are alike because they both have limited available water.
