B.
H in HF is slightly positive while O in H2O is slightly negative. So they attract in a polar bond. Btw I thought this is chemistry.
Answer:
C
Explanation:
The hot air and cold air mix making it updraft and downdraft
Definite article is used before a noun (person place or thing) to indicate that the identity of the noun is known to the reader.
indefinite article is used before a noun that is general or when its identity is not known.
I think it brings to the warm places cold air and to cold places it brings warm air