What role do predators play in maintaining the balance of an ecosystem?

Which type of neuroglia is found outside of the brain?

There is a liquid capsule inside a cup full of liquid. the cup full of liquid has salt in it and the liquid capsule has no salt in it. in which direction will the solvent flow? a. the salt does not have to move b. from the capsule to the larger cup c. equally between the capsule and the cup d. from the larger cup to the capsule

Can someone i have no idea of how to do this.