Final answer:
Ptolemy's belief that the universe was geocentric refers to an Earth-centered model, where celestial bodies revolve around the Earth. The correct answer is option a.
Step-by-step explanation:
Ptolemy believed that the universe was geocentric, which means A. Earth-centered. The Ptolemaic model, also known as the geocentric model, posited that the Earth was the static center of the universe, with the Moon, planets, the Sun, and the stars orbiting in complex patterns around it. In contrast, the Copernican model, developed later by Nicolaus Copernicus, is heliocentric, placing the Sun at the center of the solar system.
Ptolemy believed that the universe was geocentric, or Earth-centered.
In his model, Earth was at the center of the universe, and the Moon, planets, Sun, and stars all revolved around it in complex circular paths.
This geocentric model, also known as the Ptolemaic model, was purely descriptive and did not provide any explanations for the motions of celestial bodies.