Many have heard me, yet nobody has seen me. I won’t speak back unless spoken to. What am I?

An echo!

Explanation:

Many people can hear an echo, but you can't see them obviously. An echo also only happens when another sound takes place which makes sense because of the line "I won't speak back unless spoken to."

the food shivo was saving

answer; /// i do believe the correct answer is (c) public education;