The particles in matter are always moving. The more energy they have, the faster they move.  When a child has a lot of energy they will move around slower or faster?
faster

For a given medium such as air, sound has a slower speed at lower temperatures.  Mike wants his voice to travel slowly, so he will speak in a room that is colder or warmer?
colder

Lower rock layers were laid down earlier, so they are assumed to contain older fossils.  Gerald laid down many rock layers. The layers on the bottom level were likely laid first or last?
first