Material property of glass

Often on a topographic map, every fifth contour line is darkened. what is this line called? a. key b.slope c.benchmark d. index contour

Type the letter that represents the correct location for each particle type below.

Aradio signal from a gps satellite take only about 0.067 seconds to reach a gps reciever. if the speed of light is about 300,000km/s, then approximately how far away is the reciever from from the satellite?