Final answer:
The Classical Era in arts encompassed naturalistic sculpture and painting as well as structured music compositions primarily in the 18th century by notable composers like Mozart and Haydn.
Step-by-step explanation:
The organization of works during the Classical Era, which spans from the 5th through the 4th centuries BCE in Greek culture, was marked by a pursuit of naturalism and realism in both sculpture and painting. Notable for their influence on the Roman Empire and Western Civilization, Classical works often depicted naturalistic proportions and postures, as seen in the Kritios Boy and the Niobid Painter's vase. This period also saw advances in the development of perspective and multiple ground lines in painting.
In music, the term Classical Era typically refers to the latter half of the 18th century and is exemplified by the works of composers such as Mozart and Haydn, who emphasized structure in forms, melodies, and harmonies.