What evidence indicates protostars have formed
A)jets
B)bipolar outflows
C)protostellar disks
D)All of the other choices are correct.

Question

Quizplus · Accepted Answer

Jets, bipolar outflows, and protostellar disks are all evidence of protostars forming. Jets are produced by the material falling onto the protostar being heated and shocked, producing narrow streams of plasma that shoot out from the protostar's poles. Bipolar outflows are similar to jets, but instead of being strictly perpendicular to the protostar's accretion disk, they can have a more curved and spread-out shape. Finally, protostellar disks are formed when the material that is falling onto the protostar begins to flatten and rotate, forming a disk shape around the protostar. These disks can be observed directly using infrared and radio telescopes.

What Evidence Indicates Protostars Have Formed