In order to make the ionic compound CaNO3 what acid and base must have been mixed?

elements make up everything, and they combine to make compounds.

the answer is c

if the temperature drops and becomes cool

then the atmosphere can be freezing as the water vapor in the air is at maximum (100%) and can be severely cold

also can be snowing lightly as the moisture in the air will start to solidify

and btw this is not chemistry but