Which concept refers to the understanding that certain properties of objects remain constant despite changes in appearance?

The concept of conservation refers to the understanding that certain properties of objects, such as volume, mass, or number, remain unchanged despite changes in form or appearance. For example, when water is poured from a short, wide glass into a tall, narrow glass, a child who understands conservation recognizes that the amount of water is still the same, even though it looks different. This ability typically develops during the concrete operational stage of cognitive development, as outlined by Jean Piaget.

In contrast, other concepts like reversibility deal with the idea that actions can be undone or reversed, egocentrism pertains to an inability to see things from another person's perspective, and classification involves organizing objects into categories based on shared characteristics. While these concepts are essential in understanding cognitive development, they do not specifically address the notion of unchanged properties in differing appearances, making conservation the correct choice for this question.