According to our theory of solar system formation, what three major changes occurred in the solar nebula as it shrank in size?
a. its mass, temperature, and density all increased
b. its gas clumped up to form the terrestrial planets, nuclear fusion produced heavy elements to make the jovian planets, and central temperatures rose to more than a trillion kelvin.
c. it gained energy, it gained angular momentum, and it flattened into a disk
d. it got hotter, its rate of rotation increased, and it flattened into a disk

D.It got hotter, its rate of rotation increased, and it flattened into a disk

Explanation:

The nebula theory proposes that our solar system was born about 4.6billion years ago out of a gigantic interstellar cloud.

These interstellar gases are made up of some gases and some microscopic particles. The gravitational pull by the particles caused the cloud to collapse inward. The collapse triggered increase in temperature and the rate of rotation spiked. This caused the collapsed cloud to flatten into a disk with a centre bulge which later forms the sun.