Answer:
1) Gas are well separated with no regular arrangement. Liquid are close together with no regular arrangement. Solid are tightly packed, usually in a regular pattern.
2) Sound travels more quickly through solids than through liquids and gases because the molecules of a solid are closer together and, therefore, can transmit the vibrations (energy) faster.
3)The vacuum of outer space has essentially zero air. Because sound is just vibrating air, space has no air to vibrate and therefore no sound.
