how does the appearance of spiral galaxies vary? select the two correct answer.

Question

a. some are more elongated in shape thaqn others.
b. they vary in the birhgtness of stars located on their arms
c. they vary in how tightly their arms are wound
d. some have a band of stars and materials through their middle, but others do not.

Answer 1

The two correct answers regarding how the appearance of spiral galaxies varies are:

a. some are more elongated in shape than others.
c. they vary in how tightly their arms are wound.

These options reflect variations in the morphology and structure of spiral galaxies. Option b relates to the brightness of stars, which can vary but isn't a defining characteristic of the galaxy's type. Option d is less applicable since most spiral galaxies do have a central bulge, but the distinction of having a "band" through the middle isn't a standard classification criterion.