Dump piles are: O underwater waste disposal locations.
potential health hazards.
sanitary ways of getting rid of waste.
O legal in most countries.

Answer// dinosaurs emerged during mesozoic era;

Ibelieve it is c
c makes more sense when you’re trying to pair them together!

The highest point of a hill (or mountain) is a single point.
a single point can only be precisely marked with a dot. 
putting on a contour line is impossible  on a single point because the contour line is created after multiple points that have the same hight are marked, and after that, all of those points are connected with a line that creates a closed area. so the highest point, as said above, is a single point, there are no other points with the same height, so the only possible way for it to be marked is with a dot, and there is no possibility for a contour line.

Points ab and d your welcome