Question

Events involving a disk-shaped nebula occurred before the nuclear fusion that led to the birth of the solar system. Which two statements about the disk-shaped nebula are true?
Gravity caused the disk-shaped nebula to shrink.
Gravity caused the nebula to flatten out in its disk-like shape.
Rotational motion caused the disk-shaped nebula to shrink.
Rotational motion caused the nebula to flatten out in its disk-like shape.
The flattening of the disk caused the speed of rotation to decrease.
more than 1 answer (Earth Science)

Answer 1

1.Gravity caused the disk-shaped nebula to shrink.
A cloud of gas and dust started to shrink or more corectly started condensate, due to the force of its own gravity. This process started slow, but increased in velocity as more material were moving toward the center.

2.Rotational motion caused the nebula to flatten out in its disk-like shape. The nebula spined counterclockwise to conserve the angular momentum of the material of the material that were going to the center. This rotation, made the materials that were not in the center flatten out, that's why it looks like a disk.