Because the sensitivity of the human ear varies over the audio spectrum, how do many sound systems handle very high frequencies and very low frequencies, respectively, to compensate?

1. dampen; amplify
2. amplify; amplify
3. Sound systems do nothing to compensate.
4. amplify; do nothing to
5. dampen; do nothing to
6. amplify; dampen
7. do nothing to; amplify
8. dampen; dampen
9. do nothing to; dampen

Option 2.

Amplify; Amplify

Explanation:

Amplification of sound simply means increasing the loudness of the sound by modifying its electro-acoustic signals. To make very high and very low frequencies of sound audible by the human ear,  the sounds need to be amplified by the sound system amplifier.

Sound systems modify high frequencies by amplifying them, and also, they also modify low frequencies by amplifying them. This changes their wave form and brings them into the hearing range of humans.