Answer:
I repeat only the last word you say. The more I repeat, the softer I got. I cannot be seen but can be heard. What am I?
I have four fingers and a thumb, but I'm not living. What am I?
By myself, I'm practically nothing. Worthless as a leader, but when I follow a group, their strength increases tenfold. What am I?
I have three heads. Cut off one I become stronger. Cut off two I become ten.
I tell people to be careful when handling boxes.
It flows out of the soil, It burns you if it boils, And holds us in its coils, More valuable than gold, As black as it is old.