Which of the following gives the two main assumptions of theoretical models of galaxy evolution?
A)The beginning of the universe is modeled after a supernova explosion,and all the elements were produced in the proper quantities by the star.
B)Hydrogen and helium filled all of space,and certain regions of the universe were slightly denser than others.
C)Hydrogen and helium filled all of space,and all the universe was exactly the same density.
D)The universe has always been expanding,and denser areas contracted to form the first stars.
E)The universe was composed originally only of hydrogen,and all the other elements came from stars.

Question

Quizplus · Accepted Answer

The two main assumptions of theoretical models of galaxy evolution are that the universe began with hydrogen and helium filling all of space, and that certain regions of the universe were slightly denser than others. This allowed for the formation of structure and the clustering of matter into galaxies. Option A is not related to galaxy evolution, but rather to the production of elements in stars. Option C is not accurate, as the universe does have slight variations in density. Option D is partially correct, but does not include the initial conditions. Option E is also partially correct, but does not account for the fact that not all elements come from stars.

Which of the Following Gives the Two Main Assumptions of Theoretical