Final answer:
According to Piaget, the achievement that brings the sensory motor period to a conclusion is Object Permanence, as it helps build cognitive foundations.
Step-by-step explanation:
According to Piaget, the achievement that brings the sensory motor period to a conclusion is Object Permanence. Piaget considered it important because understanding object permanence helps build cognitive foundations. Object permanence is the concept that objects continue to exist even when they are not visible or present.