According to Jean Piaget's theory of cognitive development, what is the age range of the 'pre-operational stage'?

→ Under Jean Piaget's theory of cognitive development, when analyzing the capabilities of 'Hypothetico-Deductive Reasoning' and 'Combinatorial Thought' that develop in adolescents entering the 'Formal Operational Stage', which of the following statements most accurately defines the ontological and cognitive characteristics of this stage? → Which of the following psychological statements is most authentic and scientifically valid regarding the real psychological implications of 'Decentration'—a central concept under Jean Piaget's Theory of Cognitive Development defined as the advanced cognitive ability where a child can simultaneously consider, understand, and coordinate multiple aspects or dimensions of an object or situation rather than focusing on only one aspect, dimension, or feature (Centration)—and its scientific operation for students' multi-dimensional perspective, logical conservation, and cognitive flexibility in classroom teaching? → According to Piaget, in which stage of cognitive development does a child understand the concept of 'conservation'? → According to Jean Piaget's theory of cognitive development, what is the age range of the 'formal operational stage'? → According to Jean Piaget, which is the first stage of cognitive development? → According to Jean Piaget's theory of cognitive development, the trait of 'conservation' emerges in which stage? → According to Jean Piaget's theory of cognitive development, what is the age range of the 'pre-operational stage'? → According to Jean Piaget's theory of cognitive development, what is the age span for the 'Concrete Operational Stage'?