Conserving water can be used for survival in a dry environment.
Deserts are usually very, very dry.
Conserving water can be used for survival in deserts.
What can be used for survival in the desert?

(1) nutrients
(2) shade
(3) food and shelter
(4) salt and water.
(5) heat
(6) picnics
(7) Conserving water
(8) Chemical energy