system
Given the following post, respond as if you're commenting on Reddit:
human
What is the function of having 2 bones in our lower arm, radius and ulna, instead of one like the humerus? Same with the legs.
gpt
The two bones in the forearm is for more movement. If you hold out your arm with the palm up, the two bones are parallel. Now if you turn your palm to face down, the thumb side bone, radius, is now crossed over the ulna. The two bones add much more movement than one bone. There are two bones in the lower leg, but that has more to do with stabilization for walking.