Fekru’s ability is a logical thinking ability according to the theory of Conservation by Jean Piaget.
The Theory of Conservation according to Jean Piaget in child development explains that quantity remains the same even if the container to transfer such quantity is changed in size or colour
The ability to understand this shows the child has developed logical thinking ability.
This ability in children is noticed in the concrete operational stage from ages 7–11
Therefore Fekru understanding that the quantity of water did not change irrespective of the change in glass explains the theory of Conservation.
Learn more on Theory of Conservation here: https://brainly.com/question/4067071