Use you knowledge of lipids to explain why desert plants need the waxy coating on their leaves to survive?

Fats and lipids are hydrophobic which makes them water repelling compounds. Therefore, presence of a waxy coating on the outer skin of the desert plant prevents loss of water via evaporation from the skin of the plants. This helps the plant store water and increases its survival period.

they need the way coating because there isnt a lot of rainfall so the plants need to preserve the moisture they have in order to survive

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.