Question

Which of the following describes a major role of gravity in star formation?
A.
The gravitational forces of planets push gases from their atmospheres to form a star at the solar system's center.
B.
Gravity causes an interstellar cloud fragment to expand rapidly until it is large enough to form a star at its center.
C.
Asteroids passing by a solar system are pulled in by planets' gravities to form a star at the center of the solar system.
D.
Gravity compresses gases at the center of a solar nebula until temperatures are high enough for nuclear fusion to occur.

Answer 1

D

Gravity causes a molecular cloud (solar nebula) to collapse and compress gas at the center, raising temperature and pressure until nuclear fusion ignites and a star forms.