What the name for the color of the powder left behind when a mineral is rubbed across aa hard surface

The difference(s) between the grand canyon and valles marineris is/are: (a) the grand canyon was formed by water, but valles marineris was not. (a) valles marineris is much longer than the grand canyon. (c) valles marineris is much wider than the grand canyon. (d) valles marineris has large volcanoes near it. all of the above

Based on what you know about the location of the earth in relation to the sun, why is this called the goldilocks zone in other galaxies?

In the diagram below, ab and bc are tangent to o. what is the measure of