Answer:
1) A line can be defined by two points that are connected by the given line.
We can see that the line r connects the points A and B, then we can call this line as:
AB (the notation usually uses a double arrow in top of the letters)
2) In the image we can see that lines r and s intersect at the point B, then another name for that intersection is: B.
3) 3 colinear points are 3 points that are connected by a single line, an example of this can be the points A, B and C.
4) A plane can be defined by a line and a point outside the line.
For example, we can choose the line AB and the point D, that does not belong to the line.
Then we can call the plane as ABD.
