I would answer but you didn't put any pictures so I can't see what shows anything.
The air you breathe into your lungs on a daily basis mostly consist of carbon dioxide.
Answer to fill in blank would be D) Polar.
The limitations include the following:
1. The privacy of the individuals involved in the the research must be taken into consideration
2. The risk of physical and physiological well being of the person must be taken into consideration.
3. The subject must be made to understand every procedure and the risks involved before testing.
4. Only minimal exposure to risks is allowed and must have been previously tested in animals to avoid deaths.
Atmosphere, he was right let him have it^^