Oxygen gas
carbon dioxide
The most abundant element on Earth is
oxygen (chemical symbol O), and it is
essential to all the planet's life forms. As
the gas O2 it is in the lower atmosphere in
the air that is breathed
Animals breathe out carbon dioxide, and
plants take in carbon dioxide to make
nutrients that all organisms need, to make
oxygen for animals to breathe.
Aside from drinking, water is used for
cooking, cleaning, recreation (e.g.
swimming pools), and keeping plants
Ammonia is also used as a refrigerant
gas, for purification of water supplies, and
in the manufacture of plastics, explosives,
textiles, pesticides, dyes and other
chemicals. It is found in many household
and industrial-strength cleaning solutions.
Sodium chloride (salt)
Methane traps heat in the atmosphere.
Methane is also the main ingredient in
natural gas. Because methane can be
captured from landfills, it can be burned to
produce electricity, heat buildings, or
power garbage trucks.
More commonly referred to as “salt” or
“table salt,” sodium chloride is used as a
seasoning in many foods. Medically,
sodium chloride solutions are used in
catheter flush injections or intravenous
infusions, and for cleaning objects such as
contact lenses in the form of saline