Which of the following statements is true? 1.the organ system is the lowest level in the hierarchy. 2.organ systems are less complex than the organs they are made from. 3.the success of a system depends on the proper function of its parts. 4.the muscular system does not need the skeletal system to move the body.

The correct answer is the 3rd option. The success of a system depends on the proper function of its parts. FACT

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.