The energy source at the center of our galaxy is called a. ...

[frankwu]

The energy source at the center of our galaxy is called
 
  a. Cygnus X-1.
  b. the Orion arm.
  c. the Sun.
  d. Sagittarius A.

Question 2

There is a main-sequence mass-luminosity relation because
 
  a. helium fusion produces carbon.
  b. stars expand when they become giants.
  c. more massive stars support their larger weight by making more energy.
  d. the helium flash occurs in degenerate matter.
  e. all stars on the main sequence have about the same radius.

[sierramartinez]

Answer to Question 1

.D

Answer to Question 2

c

[frankwu]

TYSM

[daiying98]

Thanks for the timely response, appreciate it