The lowest elevation to which a stream can downcut is the ________.

Using the Mohs hardness scale below, which of the following statements is NOT true?

Volatiles refer to substances that ________.

Most of the pushing force driving plate motion is produced ________.

Magma tends to ________.

Volcanoes that do NOT occur along either present or emergent plate boundaries are associated with ________.

Continental coastlines that occur within the interior of a tectonic plate are called ________ margins.

The warmest global temperatures since the last ice age occurred in the ________.

A runaway greenhouse effect is an example of ________.

Milankovitch cycles describe variation in Earth’s ________.