Which bond in the acetic acid molecule is the most polar?

(-C=O) bond in the acetic acid is the most most polar bond.

Explanation:

Acetic acid is an organic acid with carboxyl group (-COOH).

In this functional group two oxygen atoms are present in which one oxygen atom is double bonded to carbon atom and another one is single bonded to the carbon atom.

(-C=O) bond is most polar bond because oxygen being electronegative in nature attracts the shared bond pairs of electrons towards itself by which formation of partial positive charges occurs on the carbon atom and partial negative charge on the oxygen atom.

geosphere and hydrosphere.

this is because the geosphere has to do with geological events, while the hydrosphere controls all water on earth.