Answer:
This is because fluids have a polar nature, so they couldn´t cross the lipidic bilayer that constitutes the plasma membrane
Explanation:
Plasma membranes are contituted by lipid bilayers. These kind of compounds are hidrophobic (they reject water) and don´t permit the freely passage of hidriphilic molecules that can disolve in water, constituing fluids. Because of that cells developed transport mechanism like endocytosis.
Cohesion is water sticking to water. adhesion is water sticking to another thing, think of it as you're adding something to the water molecules. add-hesion