Explain how an echo is made. why are echos heard sometimes but not others

Explain how an echo is made?

➜ An echo is a sound that is repeated because the sound waves are reflected back. Sound waves can bounce off smooth, hard objects in the same way as a rubber ball bounces off the ground. Although the direction of the sound changes, the echo sounds the same as the original sound.

Why are echos heard sometimes but not others?

➜ So, the reason that echoes aren't heard in rooms is that the reflected sounds are received in less than 0.1 seconds, or the reflecting surfaces are at distances of less than 17 meters. Reverberations can also be heard in an empty apartment.

there is no correct list among the choices you've provided.

the list might look something like this:

-- baby human

-- piccolo

-- flute

-- soprano singer

-- trumpet

-- tenor singer

-- trombone

-- baritone singer

-- baritone horn

-- bass singer

-- tuba

since i had to make up the list myself, i made it easy on myself, and i didn't try to shuffle the string instruments and woodwinds into it too.

not moving. pos accel,