i am having trouble with knowing the diffrences between parallel lines and skew lines. i have a problem that says, if two lines do not intersect, are they always parallel? can i prove the statement wrong? or is skew same as parallel?

i also have a problem with this one:

if two parallel lines, are cut by a transversal, then the corresponding angles are congruent. they tell me to point out which angles are corresponding. also same question just altrnate interior angles. which angles are they?

one last problem that i have in my homework is in triangles. they tell me to figure out the interior angles. okay, so i know that a triangle must add up to 180 degrees, so i basically figured that out. then they ask me to figure out exterior. how do i figure that out?

thank you!