What is included in the "solid part of the earth"?

When we organize patterns in order to perceive an entire stimulus rather than just its parts, we are using

The formation of the planet uranus is estimated to have occurred approximately when?

One of the main reasons societies settled along rivers in the neolithic era was because a) the village elders demanded it. b) the land there was more valuable. c) it was more safe and secure there. d) it provided irrigation for farming.