Most people can survive only a few days without water.
Water is made up of h2o molecules.
Most people can survive only a few days without h2o.
What is something people can survive only a few days without?
Options:
(1) Shelter
(2) Food
(3) O3
(4) NaCl
(5) urea
(6) H20
(7) H2O
(8) Salt