The mesozoic era is divided into the triassic, the jurassic, and the cretaceous. these divisions of the geologic time scale are called

unconformities.
eras.
periods.
decades.

Which of the following types of nonrenewable fuel sources requires the storage of radioactive waste? a. coal b. nuclear c. solar d. oil

This is a 2017 topographic map of puerto rico in the united states, and i'm sorry that people there have suffered such a disaster. i want to ask, what do the yellow dots and areas represent on this graph? and the blue area and the little blue circle, and the little blue sign that looks like a signal tower, what do they stand for?

What’s word for a smaller earthquake that follows the main shock of a large earthquake?