Which of the following is true of children's zone of proximal development? 1) It refers to an area in which children develop new cognitive skills as a function of working with more skilled people. 2) It refers to an area in which children develop new cognitive skills through self-learning. 3) It refers to an area in which children develop new cognitive skills through self-learning. 4) It refers to an area in which children develop their drawing skills on their own with the passage of time.