The blank could be filled in with humerus since it is the longest bone in the leg.
Normal cells<span> listen to signals from neighboring </span>cells<span> and stop growing when they encroach on nearby tissues (something called contact inhibition.) </span>Cancer cells<span> ignore these </span>cells<span> and invade nearby tissues. Benign (non-</span>cancerous<span>) tumors have a fibrous capsule.</span>
