How do animals adapt to their environment?

In nature, animals have to adapt to living on earth, underground, in water and in the air.
Those animals that lead a terrestrial lifestyle have limbs for moving on the ground, have a kind of protection from both enemies and weather conditions, they have a camouflage, for example, many felines have spots to merge with the terrain and pads on their paws to be quiet sneak up on the victim. In cold climates, animals have thick skins and thick fur.
Aquatic animals are adapted to move in water. For example, fish have a streamlined body, gills – to breathe underwater and fins – to swim. Some are adapted to a semi-aquatic lifestyle, for example, frogs, otters, beavers have membranes on their paws, but do not have gills.
Underground animals are basically devoid of eyes, they do not need them underground.
The hosts of the air environment are birds, they move mainly through the air, for this they have wings, some birds and bats can hunt in the air.