True or false: Even though copper, gold, silver, and platinum can exist as native metals meaning that they can be found in their free elemental form, most metals have to be mined from a mineral ore that then needs to be processed to isolate the metal.

the part of the wave he is travelling on is the crest

luster is not a good characteristic to use by itself because luster is the property of minerals that indicates how much the surface of a mineral reflects light. the luster of a mineral is affected by the brilliance of the light used to observe the mineral surface.

blue light is scattered in different directions by the tiny molecules of air. blue is scattered more than other colours because it has a shorter distance to travel which results in smaller waves. this is why we see a blue sky most of the time.