Which statement describes clean air as a natural resource? select three options.

a,d,e

Explanation:

its a,d, and e because clean air keeps us alive and other organisms need it to stay alive

B Air pressure is created by the weight of the atmosphere pushing on Earth’s surface

D Denser air is heavier than less dense air.

E Air is less dense at higher altitudes.

Explanation:

Hope this helps you and you pass your test good luck:D

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .