HELP ASAP PLEASE!!
Which of the following is most useful in the identification of a mineral?
A. size
b. weight
C. luster
D. length

Need in all of themmm only answer if you know pls

Moon effect. some people believe that the moon controls their activities. if the moon moves from being directly on the opposite side of earth from you to being directly overhead, by what percentage does (a) the moon's gravitational pull on you increase and (b) your weight (as measured on a scale) decrease? assume that the earth–moon (center-to-center) distance is 3.82 × 10^8 m, earth's radius is 6.37 × 10^6 m, moon's mass is 7.36 × 10^22 kg, and earth's mass is 5.98 × 10^24 kg.

Explain why electric current cannot exist if a current doesn't have a voltage source.