Answer:
They are different exercises with different objectives so I would say they are all effective.
Planks or prone holds are a core stabilization exercise which is an isometric hold. You are bracing your core to build core endurance which is important for any movements in life which require the core to be braced.
Push-ups while they involve the same core stabilization, you are now moving your upper body through a compound movement. Your arms and chest are more likely to fatigue before your core, as such this exercise will help build strength and endurance through your pecs (chest), deltoids (shoulders), and triceps (arms).
Range of motion develops stamina and endurance as one is able to increase their reps. Different width hand positions and placement of hands such as fingers pointed out, in, backward varying which muscles are affected more.
