Question

question 3
what is the difference between an sbb galaxy and an sb galaxy?
the sbb galaxy has a bar of material passing though the center and the sb galaxy does not.
the sbb galaxy has more tightly wound spiral arms than the sb galaxy.
the sbb galaxy is more elliptical than the sb galaxy.
the sbb galaxy is an irregular galaxy but the sb galaxy is not.
the sbb galaxy has less tightly wound sprial arms than the sb galaxy.

Explanation:

In galaxy classification, the "B" in SBb indicates a barred spiral galaxy (with a central bar of material), while Sb is an unbarred spiral galaxy. The tightness of spiral arms is indicated by lowercase letters (e.g., a=tight, b=moderate, c=loose), so both SBb and Sb have moderately wound arms. SBb is not elliptical or irregular.

Answer:

The SBb galaxy has a bar of material passing though the center and the Sb galaxy does not.