Organizing objects according to size is

• A. Sequencing
• B. Classification
• C. Seriation
• D. Mediation

Answer: (C)

Seriation is the ability to arrange objects in a logical order based on a property such as size. When you have a set of items and ask a child to line them up from smallest to largest, that’s seriation in action. It helps kids compare which item is bigger or smaller and understand ordinal relationships that underpin early math reasoning.

This differs from sequencing, which is about ordering events or steps in a process; classification, which groups items by shared attributes; and mediation, which involves resolving disagreements between people. So organizing objects by size is a classic example of seriation.