The reason that you can tell that it was chemical is because you can see the bubbles forming. This means that it is giving off a gas.
D brushing teeth removes plaque and food particles
Answer by JKismyhusbandbae: stimulant.
Depressants are drugs that slow the central nervous system. Depressants are widely used and inhibit the function of the central nervous system also known as stimulant.
Not including all the terms but this is right.
The others are just thrown in there somewhere.
vena cava
right atrium
right ventricle
Pulmonary aretery
Left ventricle
left atrium
Airtic valve
Aorta
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!
