Answer:
polar
Step-by-step explanation:
The basic characteristics of any solvent is to be able to dissolve all sort of molecules or substance in it. Thus polarity is an important characteristics of solvents
For all living organism water is the most specific form of solvent. Water being polar is able to form electrostatic interactions with other polar molecules and ions. The positive ions/molecules get attracted to either the partially positive or partially negative ends of water based on their own charge
Thus, polarity is an essential trait of any effective solvent.