Sound waves can't travel through
a. an elastic material.
b. a liquid.
c. a vacuum.
d. a solid.

when the use of electricity burdens the fuse and miniarure circuit beakers and there is a possibility of a fuse then they automatically cut off the electricity supply to your homes and after you fix the problem u jzt switch it on and it continues the supply of electricity to ur homes

i am pretty sure it is c because when people are closer together, they cannot move as freely. picture being in a mostly full elevator, for instance. the people are right next to you, and you can barely move.