it grows on ground because it WANTS to take in water from the moisture of the air (don't copy this i GUESSED)
humidity too low
Aerial roots typically grow above the ground or on tree branches, and they can absorb moisture from the air, fog, or rain. Some aerial roots also have a porous outer layer that allows them to absorb moisture and nutrients from the surrounding environment. Additionally, some aerial roots can grow down to the ground and absorb water and minerals from the soil, transporting them to the trunk and branches of the plant.
to get oxygen for the plant or because there wasn't enough room to grow in the soil
aerial roots - See related links to read about stilt-roots, pneumatophores, root knees, and plank roots.
Mangrove trees have aerial roots (roots above the soil) as they grow very close together and therefore don't find enough oxygen (O2) underground.
Because orchids are designed to be an aerial type of plants
allow them to obtain oxygen from the air, such as aerial roots.
Aerial roots
the examples of aerial roots is mangroove tree
roots that never touch the ground for example orchids
Older banyan trees are characterized by their aerial prop roots that grow into thick woody trunks which, with age, can become indistinguishable from the main one.
Aerial roots which are roots that never touch the ground.Fibrous roots which are roots that are thin and branching.Tap roots have a main stalk-like root that plunges deep into the ground.The last is Prop roots which are roots that usually grow at the bottom of a plants stem that help supportand prop it up so it will not get knocked over.