A line segment has two endpoints unlike a line where a line is infinite with no end! :) Think of a line segment essentially just being two points on a line. :)
Imagine there are 4 sits for fill for the debate team
we can fill the first sit in 35 different ways, second sit we only have 34 choices , third sit 33 and last sit 32 ways to possible fill it.
35·34·33·32=1,256,640 possible ways the team could be form
What is the apply??? Put all of the select all that apply so I can help you