6 DO
Which are examples of a medium?
water and air
amplitude and wavelength
crests and troughs
compressions and rarefactions

water and air

Explanation:

The examples of medium from this problem is water and air.

A medium is an agency or a means of propagating energy, waves or even facilitating a chemical reaction.

Fluids are very good medium in chemistry for chemical reactions. The two most common media used are air and water.

In physics, a vacuum is an empty space that has been evacuated. It also serves as a medium to study some physical phenomenon.

explanation: it gains negative electrons, therefore becoming negatively charged. as charge cannot be created, nor destroyed, only transferred, this leaves the wool positive. now that they have opposite charges, the two items attract.