Shawna describes her 5-year-old son Tommy as "egocentric" when talking to her next-door neighbor. According to Piaget, this descriptor would be most appropriate for explaining which of Tommy's behaviors?

1. body tissue that is connected to and moves the bones in the body hypertrophy 2. the ability of a muscle to move a weight repeatedly, or for an extended period of time tendon 3. the increase in the size of a muscle fiber in response to resistance training muscle strength 4. the most amount of weight a muscle can move at a single time skeletal muscles 5. the decrease in the size and strength of a skeletal muscle when it is not used atrophy 6. strong body tissue that connects the muscles to the bones muscle endurance