Answer:
rotating cloud of dust and gas.
Step-by-step explanation:
- The nebular theory is a theory that explains the formation of the solar system and also its evolution.
- According to this theory, the solar system evolved from a nebulous material which is nothing but a huge nebula made up of dust particles and heavy gases.
- This hypothesis helped to clarify several existing properties of the solar system such as the nearly circular and coplanar orbit of the planets and the fact that their motion is in the same direction as the rotation of the sun.