How can a specific hair collected at a crime scene be matched to a group of people?

A single hair has many strands of DNA. One hair can be matched to a group of people if they all have the same DNA.

Another way one hair could be matched to a group of people is if it also got other poeple's DNA on it like if it got someone else's blood on it.

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.

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.