Question

Answer all the following questions by putting a circle around a letter A.B.C or D

1. Air contains about
A. 3% carbon (IV) oxide.
B. 4%noble gases.
C. 21%oxygen
D. 69% nitrogen​

Answer 1

C. 21%oxygen

Step-by-step explanation:

Dry air contains 78.09% nitrogen, 20.95%oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases.