The __________ is the rapid change in seawater density from less dense water above to more dense water below, whereas the __________ is the gradual boundary between warmer water above and colder water below.

  This mineral, better known as rock salt, has many uses, including de-icing sidewalks. 

Which of the following letters marks the path of the Sun, the Moon, and planets as seen from the Earth?

  Which of the following is NOT a way in which specific rock types can be distinguished from one another?

A sill is a(n)

On the figure below, what are A, B, and C, respectively?

A refracting telescope works by use of a(n) __________, whereas a reflecting telescope uses a(n) __________.  

__________ melting occurs at subduction zones because the downgoing plate __________.

Which of the following techniques is able to determine the farthest distance of space objects?

The decrease in altitude of the tropopause with increasing latitude results in the polar-front jet stream