Most children successfully acquire conservation skills during the stage of cognitive development.\

The answer is, during the:

concrete operational stage of cognitive development

Quick information:

This concrete operational stage of cognitive development is the third stage of Piaget's theory of cognitive development. It is considered as a major turning point in the child's cognitive development. And, children on this stage is able to incorporate inductive logic.

answer; /// i do believe but not sure(nazi propaganda)//(anti-semitism); ( holocaust) plz check first; ///good luck

answer; /// the above statement is (true);