Distance and time, distance because that's how far and time because that's how long
Velocity, because if an object is in motion with no direction we will consider it as speed, but if it has direction we will consider it as Velocity. Hope it helps
Melting, boiling, and freezing are state changes!
Hope this helps! Any questions please just ask! Thank you so much!
Answer:

Explanation:
n = Order = 1
c = Speed of light = 
f = Frequency = 
= Angle = 
Lattice spacing is given by

The lattice spacing of the crystal is 
Check bing for the answer