Question

two opposing forces, ____ and ____, are pulling and pushing all the time on the upper and lower surfaces of beams. a downforce; crossforce b gravity; levity c tension; compression d time; distance

Explanation:

Tension is a pulling force and compression is a pushing force. When considering forces acting on the upper and lower surfaces of beams, tension and compression are the relevant opposing forces. Gravity acts down - ward and levity is a non - existent force in physics in the context of real forces acting on beams. Downforce and crossforce are not the main opposing forces on beam surfaces, and time and distance are not forces.

Answer:

C. tension; compression