Which concept is important for understanding during the Concrete-Operational stage?

The concept that is important for understanding during the Concrete-Operational stage is the development of logical reasoning. This stage, according to Piaget's theory of cognitive development, typically occurs between the ages of 7 and 11 years. During this phase, children begin to understand the concept of conservation, can perform operations mentally, and follow logical thought processes when dealing with concrete objects or events.

Children in this stage develop the ability to think logically about concrete situations, which allows them to classify objects, understand the order of events, and solve problems using a logical framework. For example, they can understand that if you pour water from one glass to another, the amount of water remains the same despite the change in shape. This new ability to think logically about tangible, physical objects is a significant shift from the previous stage, where reasoning was more intuitive and less structured.

In contrast, the other options represent characteristics that do not typify the Concrete-Operational stage. Logical reasoning is indeed developed during this stage, while abstract thinking skills and illogical thought processes are more associated with different stages or developmental issues that are not typical at this point in a child's cognitive development.