Five-year-old oliver complained to his mom that the pizza was not big enough. oliver's mom cut the pizza into smaller slices, thus making him happy, as he believed the pizza had become larger. oliver lacks the concept of

- The answer is Concept of conservation.

- It is a logical thinking ability. Conservation refers to the ability to determine that a certain quantity will remain the same despite adjustment of the container, shape, or apparent size.

- Conservation is measure and test the ability of the child to see that some properties are still be conserved after having a physical transformation.