What Do We Mean by Accretion in the Context of Planet

Multiple Choice

What do we mean by accretion in the context of planet formation?

A) the formation of moons around planets
B) the growth of planetesimals from smaller solid particles that collided and stuck together
C) the solidification of ices,rocks,and metal from the gas of the solar nebular
D) the growth of the Sun as the density of gas increased in the center of the solar nebula