How do we determine the amount of dark matter in elliptical ...

[bcretired]

How do we determine the amount of dark matter in elliptical galaxies?
 
  A) We measure the broadening of the galaxy's absorption lines to infer the speeds of stars at different distances from the galactic center.
  B) We measure how fast the galaxy rotates as a whole.
  C) We measure the orbital velocities of star-forming gas clouds in the outer portion of the galaxy.
  D) We count the number of stars in the galaxy. Combining this with the galaxy's volume, we can calculate the galaxy's density.
  E) We search for dark lanes of dust and black holes within the galaxy.

Question 2

At the center of the Sun, nuclear fusion converts hydrogen into
 
  A) radiation and elements such as carbon and nitrogen.
  B) helium, gamma rays, and neutrinos.
  C) hydrogen compounds such as methane.
  D) radioactive elements such as uranium and plutonium.
  E) molecular hydrogen.

[s.meritte]

Answer to Question 1

A

Answer to Question 2

B

[bcretired]

Thank you!

[s.meritte]

Always glad to help...