____ Occurs When Most of the Material Collapsing to Form

Multiple Choice

____ occurs when most of the material collapsing to form a protostar has fallen into a disk around the star,and a strong wind from the warm protostar ejects material from its poles.

A) An emission nebula
B) Hydrostatic equilibrium
C) The proton-proton chain
D) The thermonuclear fusion of hydrogen
E) A bipolar flow