Which best defines cohesion?
a: cohesion is caused by polar water molecules attracting each other.
b: cohesion is caused by polar water molecules repelling each other.
c: cohesion is caused by polar water molecules repelling and not mixing with non–polar molecules.

The correct answer is A - Cohesion is best defined as polar water molecules attracting each other. Water molecules are very cohesive, and this explains why water has surface tension. Strong hydrogen bonds are formed between water molecules, which is why droplets will normally form when water meets another force.