Question

1. campers shouted toward a canyon wall. what characteristic of sound best explains why the campers heard an echo?

sound waves traveled slowly down the canyon.
sound waves were absorbed by the canyon wall.
sound waves reflected off the canyon wall.
sound waves were refracted around the canyon.

Explanation:

An echo occurs when sound waves bounce off a surface. If sound waves were absorbed (second option), no echo would be heard. The speed of sound (first option) doesn't explain the echo phenomenon. Refraction (fourth option) is about bending of sound waves due to medium changes, not relevant here. Reflection (third option) is the key - sound waves reflecting off the canyon wall cause the echo.

Answer:

Sound waves reflected off the canyon wall.