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!
Its the same thing haha there are two types indica and sativa. Indica makes you tired and want to sleep while on the other hand sativa relaxes your body.
I'm not sure if I understand your question correctly but we food is something that will not always be there for us but it is something that we need and we crave. Food is useful in many ways and helpful. We need love because due to lonliness many have died by commiting suicide.
