Which of these is an example of investigating an intensive properly?
weighing sand in a bag
measuring the length of wire
determining if a rock is magnetic
recording the volume of water in a cylinder

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation:

plasma - state of matter made up of electrically charged particles