In psychology, concepts can be divided into two categories: and

In psychology, concepts can be divided into two categories: Realizable and Unrealizable. Realizable concept may be or may be not realized, while unrealizable concepts cannot possible be realized. 

In psychology, concepts can be divided into two categories namely natural and artificial. Natural concepts are produced in a natural way by means of experiences. They can be improved from either direct or indirect experiences in life. Whereas for artificial concept, it is defined by a particular set of traits. Different properties of geometric shapes are good examples of artificial concepts. 

The adams apple, or laryngeal prominence. is a feature of the human neck, and is the lump or protrusion that is formed by the angle of the thyroid cartilage surrounding the larynx seen especially in males.