In the double-exhaust model, the radio lobes of a radio galaxy ...

[nummyann]

In the double-exhaust model, the radio lobes of a radio galaxy are inflated by
 
  a. jets of excited gas flowing from the central galaxy.
  b. jets of high-energy sound waves flowing from the central galaxy.
  c. a disk of ionized material that orbits very near a supermassive black hole.
  d. dark clouds of very cold gas and dust.
  e. None of the other choices are correct.

Question 2

Giant and supergiant stars are rare because
 
  a. they do not form as often as main-sequence stars.
  b. the star blows up before the giant or supergiant stage is reached
  c. the giant or supergiant stage is very short.
  d. the giant or supergiant stage is very long

[atrochim]

Answer to Question 1

a

Answer to Question 2

c

[nummyann]

Thank you!

[atrochim]

Always glad to help...