Ability to master (most babies can do it): wave goodbye; Can pinch things with thumb and forefinger; Skilled climbing, the stomach can leave the ground.
Developing ability (half of babies can do it): being able to correctly distinguish and call out "father" and "mother"; You can express what you want by gestures.
Advanced ability (only a few babies can do it): being able to stand for a few seconds without holding anything; Can put things in containers.