How can a small area in the middle of the desert provide an organism what it needs to survive

Deserts are the region where there is abundant sand and the amount of precipitation level is significantly low. It is comprised of low vegetation cover and various lives exist in the desert. The desert biome is characterized by a hot and relatively dry type of climate.

A small region in the middle of the desert is generally found to contain a certain amount of water and this is known as an oasis. The organism in the desert are dependent on these water bodies, and it helps them to exist and enhance their growth and development.  

Thus these water bodies provide the necessary elements for them to survive.

only about ten percent of the energy at one trophic level is passed on to organisms at the next trophic level. the remainder of the energy is used in life processes or lost as heat.