What name identifies the technique of gradual shifting from light to dark through a successive gradation of tones across a curved surface—a technique often used to create the illusion of three dimensions in two-dimensional media?

Chiaroscuro.

Explanation:

Based on the information provided within the question it can be said that the technique that is is being described in this scenario is known as Chiaroscuro. This technique mainly uses very strong contrasts between light and dark in order to create a volumetric atmosphere within two-dimensional art in order to simulate three-dimensional objects and figures.

the economic difference between the three colonial regions. shipbuilding, whaling, fishing, and trapping where also main factors to the economy. the southern regional colonies economy was based on sugarcane, rice, cotton, tobacco, and indigo.