When 18-month-old kayla was at her day-care center, she understood that her father would be picking her up at the end of the day. kayla’s understanding that her father continues to exist even when he

When 18-month-old kayla was at her day-care center, she understood that her father would be picking her up at the end of the day. kayla’s understanding that her father continues to exist even when he cannot directly be seen or heard demonstrates?