I really need help with these :(

i need the answer to this too but idk it ; -;

ill do it for 100, also this isnt 80 its 40

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.

answer///isobars;