Q: Which list contains only things that are part of our solar system? ----

A: planets, moons, comets

Q: A scientist combines oxygen and hydrogen to form water. This combination illustrates that water is ----

A: a compound.

Q: Although change in multicellular species usually takes thousands of years, some species of bacteria undergo major changes in just a few years. One reason for this difference is that these bacteria ----

A: reproduce very quickly

Q: Which species have been on the Earth for the shortest amount of time? ----
A: Humans