Water is often referred to as the "universal solvent" because it can dissolve many substances effectively. The kinds of substances that mix easily with water are ionic and polar substances.
Ionic substances (like salts) dissociate into ions in water, while polar substances (like sugars) interact well with water molecules due to similar polarity. Nonpolar substances, such as lipids and oils, do not dissolve well in water due to their lack of polarity.
So, the correct answer is ionic and polar substances.