A grand-design spiral of type SBa has all of these EXCEPT
A) tightly wound spiral arms.
B) a central bar.
C) about 25% gas and dust.
D) a halo of globular clusters.

Question

Quizplus · Accepted Answer

Grand-design spirals, especially of type SBa, are characterized by tightly wound spiral arms (A), a central bar (B), and often a halo of globular clusters (D). However, they do not typically have as high as 25% of their mass in gas and dust (C); this proportion is more characteristic of later-type spirals.

A Grand-Design Spiral of Type SBa Has All of These