Question

thought earth did not move because its movement was not obvious from the surface of the planet. the greeks also believed that an invisible sphere surrounding our planet contained the stars. this sphere rotated, explaining the apparent movement of constellations over time. the milky way galaxy has spiraling arms. the spiraling arms of the milky way galaxy are part of a large sphere of rotating stars large rotating disk of stars small sphere of rotating stars small rotating disk of stars

Explanation:

The Milky Way is a spiral galaxy. Spiral galaxies have a large rotating disk - like structure. The spiral arms are part of this large rotating disk which contains numerous stars. A sphere - shaped structure (whether large or small) is not the typical shape for the main body of a spiral galaxy where the spiral arms are located. A small disk would not be in line with the scale of a galaxy like the Milky Way.

Answer:

large rotating disk of stars