1. The problem asks which concept is developed when learners fill a container with water and transfer it to another container of different shape and size. 2. This activity demonstrates that the amount of water remains the same despite the change in container shape or size. 3. This illustrates the concept of conservation, which means understanding that quantity does not change even when its appearance changes. 4. The other options like identification, ordering, sorting, and classification do not directly relate to this activity. 5. Therefore, the correct concept developed is **Conservation**.