Organisms which live in different habitats are diverse mainly because of variations in

(a) temperature

(b) light

(c) soil

(d) water

Annual variations in the intensity and duration of temperature, resulting in distinct seasons. These variations together with annual variation in precipitation account for the formation of major biomes such as desert, rain forest and tundra. Regional and local variations within each biome lead to the formation of a wide variety of habitats. The key elements that lead to so much variation in the physical and chemical conditions of different habitats are temperature, water, light and soil.