A nurse is teaching parents of infants about the concept of object permanence in infants. Which statements should the nurse include in the teaching? (Select all that apply.)

“Object permanence is fully developed by 6 months of age.”

"Understanding object permanence is a key milestone in cognitive development."

“Playing peek-a-boo can help reinforce the concept of object permanence.”

“Before developing object permanence, infants believe that objects cease to exist when out of sight."

"Object permanence typically begins to develop around 12 months of age.”