Answer:
13: Skew
14: Parallel
16: Intersecting
17: Skew
18: No
19: Yes
20: No
21: Yes
Explanation:
Skew is when 2 lines dont intersect, nor are parallel (On different planes)
Parallel is when 2 lines are on the same plane, and will never touch
Intersecting is when any set of given points go through each other