For the first time in his young life, nemo is able to look at photos of aquatic animals and can classify them as mammals or fish. he is also able to order them from smallest to largest. these skills indicate that nemo has likely just entered the stage of cognitive development.

Answer is concrete operations.

Explanation:

Cognitive development describes how the children process information and learn to evaluate , compare and analyse cause and effect. It also explains that children pass through the stages of mental development., which are sensorimotor, preoperational, concrete and formal stages.

These will bring about the development of skills, problem solving and knowledge in the children.