Process of Science: What evidence do scientists have that ...

[faduma]

Process of Science: What evidence do scientists have that supermassive black holes exist?
 
  What will be an ideal response?

Question 2

The atmosphere of Mars is made mostly of
 
  A) nitrogen
  B) carbon dioxide
  C) hydrocarbons
  D) ammonia

[ansleighelindsey]

Answer to Question 1

Observations of orbiting stars and gas clouds in galaxies show that they are orbiting extremely massive (tens of millions of solar masses) objects that are invisible.

Answer to Question 2

B

[faduma]

Thanks for the timely response, appreciate it

[AmberC1996]

Gracias!