A research lab in San Francisco has built a robot that is able to walk, talk, and interact with humans. The robot is built of small bits of metal and plastic, which when put together create the circuits and pistons and support structures that organize the robot's interior. These circuits, pistons and support structures are divided into parts collections based on the jobs that they perform together, such as information parts, signal parts, or movement parts. Groups are different parts collections organized together to perform a specific job related to a key task, such as moving the robot body. Together all of the groups make the whole robot function in some ways like a living thing. What part of the robot is most similar to the organ level of a live human?