I would have to say the answer is C.
A is incorrect since hydrogen is not an air pollutant.
B is incorrect because ozone is most definitely one of the top.
And D has cyanide which is a chemical for suicide during wars.
Hope this helps!
Answer:
A
Explanation:
I hope this helps have a great day
Answer: vit D
Explanation:
To help strengthen bones.
Answer:
A. Ask the person whether he/she is choking.
Explanation:
Then signaling that they cant breath or talk, then proceed.
