oxygen
ammonia and some types of gas based carbon.
oxygen
ozone
nitrogen
ozone
Oxygen.
Oxygen, now about 20% of the atmosphere, was not part of the original atmosphere of hthe Earth. It was produced by plants, after life developed.
gas-gas
The Gas Giants have a deep gas atmosphere and earth have a not so deep atmosphere
The Gas Giants have a deep gas atmosphere and earth have a not so deep atmosphere
Nitrogen
Oxygen gas
The Gas Giants have a deep gas atmosphere and earth have a not so deep atmosphere