A. Oxygen
B. Nitrogen
C. Helium
D. Argon
E. Water vapor
A. The rusting of iron
B. Solar radiation
C. Decomposition (rotting) of dead animals
D. Burning of coal
E. Green plants
A. The mesosphere
B. The troposphere
C. The thermosphere
D. The stratosphere
E. The exosphere
A. The thermosphere
B. The troposphere
C. The stratosphere
D. The mesosphere
E. The exosphere
A. The stratosphere
B. The exosphere
C. The mesosphere
D. The troposphere
E. The stratosphere
A. Argon
B. Neon
C. Ozone
D. Carbon dioxide
E. Nitrogen
A. First
B. Second
C. Third
D. Fourth
E. Fifth
A. Nitrogen
B. Neon
C. Chlorine
D. Carbon dioxide
E. Helium
A. Decreases
B. Increases
C. Decreases for a few miles, then increases
D. Increases for a few miles, then decreases
E. Has no predictable pattern
A. True
B. False