What are the reasons for the difference between natural complexes on earth?

Natural complexes differ from each other for several reasons, such as climate, humidity, precipitation, relief, etc. For example, in hot and constantly humid places of the planet, evergreen tropical forests grow. And in places where it is hot, but very arid, such natural complexes as deserts or semi-deserts appear. And in the northern regions of the planet, where low temperatures are always observed and little precipitation falls, or in the high-mountainous regions, tundra and high-mountain tundra are formed.