Question

1. reflection occurs when a wave ________. travels along a surface separating two media bounces off a surface it cannot pass through passes through a surface of a different density

Explanation:

Reflection is a wave phenomenon. When a wave meets a surface it cannot pass through (like a light wave hitting a mirror which it can't penetrate), it bounces back. Traveling along a surface separating two media is not reflection. Passing through a surface of different density is refraction (change in direction due to speed change as wave enters new medium).

Answer:

bounces off a surface it cannot pass through