The vaccine ofcourse. They helped in making the vaccine.
It can be caused by chemical reactions like sulfur dioxide and nitrogen oxides. These can rise very high in the atmosphere. They can mix in with oxygen and rain and thats where you get your acid rain from
I hope this is helpful <span />
Answer:
GAS, LIQUID, CLOUDS
Explanation:
Water can be in three states: solid, liquid and gas, passing from one to another depending on the pressure and temperature.
In this complementation exercise.
When the water cools down the GAS goes to the LIQUID state, these small drops unite and form the CLOUDS
