How are objects in the universe held together by

Objects are held together and remain there in the universe by powerful gravity.

Explanation:

Without gravity humans would not be able to walk on earth. We would all lose the gravitational pull and start floating.

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:

c (diamond),

sio2 (quartz)