I believe you are asking about the "triangle" we were tought a simple triangle. Cells at the bottom because there are the most of them, tissues next, organ next, and organ system at the top. So I believe the answer you are looking for is Organ System.
Answer:
Piaget places preschoolers in the pre-operational stage, meaning before mental actions.
Explanation:
Piaget's theory states that three abilities or standards must be met before operations or mental activity can exist.
