2 points
In order to draw a straight line, two unique ordered pairs are needed. This is because two unique points determine a line and an ordered pair represents a point.
Two distinct (different) points are needed to determine a line.
You need any number between 10 to 20 distinct end points.
Only two are necessary to define a line. But infinitely many are required to DRAW it.
6
12 lines
4
Two.
Only one.
5 lines
45 points