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Author Question: The__________is a theory that proposed to account for spiral arms as compressions of the ... (Read 30 times)

biggirl4568

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on: Jul 27, 2018
The__________is a theory that proposed to account for spiral arms as compressions of the interstellar medium in the disk of the galaxy.
 
  A) spiral relativity theory
  B) spiral density wave theory
  C) spiral tracer theory
  D) spiral arm theory

Question 2

In 1912, after studying a star cloud called the Small Magellanic Cloud, Henrietta Leavitt concluded that:
 
  A) stars are eternal and unchanging.
  B) the brightest stars have the shortest pulsation periods.
  C) the Sun and Earth are near the edge of our Galaxy.
  D) there was a relationship between pulsation periods and luminosities of stars.


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sylvia

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Reply #1 on: Jul 27, 2018
Answer to Question 1

B

Answer to Question 2

D


biggirl4568

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Reply 2 on: Jul 27, 2018
Thanks for the timely response, appreciate it

dreamfighter72

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Reply 3 on: Yesterday
Excellent

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