Question

all of the following are examples of mediums except... water air earths crust outer space

Explanation:

In physics, a medium is a substance through which a wave can propagate. Water, air, and Earth's crust can all act as media for different types of waves (e.g., sound waves in air and water, seismic waves in Earth's crust). Outer - space is a vacuum and lacks the particles necessary to act as a medium for most common waves (like sound waves which require a material medium to travel).

Answer:

Outer Space