As he grew, he kept learning and experimenting with Legos, electronics, and the muscles he did have.
When he was 18, David built an artificial arm he could control. He named it the MK-1. He could use the
arm to pick up objects and perform daily tasks. It was even strong enough to do push ups! David
continues to improve on the MK-1. So far he has created several updated versions of the arm. This even
earned him a nickname: HandSolo.
How does the author support the central idea?
comparing the different versions of David’s artificial arm
explaining who David is and where he is from
by explaining what David built and why he has his nickname
showing how strong the artificial arm was