Both RR Lyrae and Cepheid variable stars are stars that, when on ...

[cnetterville]

Both RR Lyrae and Cepheid variable stars are stars that, when on the main sequence, were considered to be:
 
  A) low mass.
  B) intermediate mass.
  C) high mass.
  D) zero-age main sequence.
  E) blue stragglers.

Question 2

The period from about 100 seconds up to 15 minutes after the Big Bang is the:
 
  A) Radiation Era.
  B) Lepton Epoch.
  C) Nuclear Epoch.
  D) Decoupling Epoch.
  E) Matter Era.

[krakiolit]

Answer to Question 1

C

Answer to Question 2

C

[cnetterville]

Gracias!

[robbielu01]

TYSM