Where is the crest and the trough on a wave

Which statement is a proper biconditional statement for the conditional statement: if a line intersects a line segment at its midpoint, then it is a segment bisector. if a line is a segment bisector, then it intersects the line segment at its midpoint. if a line does not intersect a line segment at its midpoint, then it is not a segment bisector. a line intersects a line segment at its midpoint if, and only if, it is a segment bisector. if a line is not a segment bisector, then it does not intersect the line segment at its midpoint.

Asap will mark geography final plz ! what are the benefits of international aid? (give me the right evidence )

Suggest 3 different reasons why there is an ageing population in the uk .