What do astronomers mean when they say that we are all star ...

[daltonest1984]

What do astronomers mean when they say that we are all star stuff?
 
  A) that life would be impossible without energy from the Sun
  B) that Earth formed at the same time as the Sun
  C) that the carbon, oxygen, and many elements essential to life were created by nucleosynthesis in stellar cores
  D) that the Sun formed from the interstellar medium: the stuff between the stars
  E) that the Universe contains billions of stars

Question 2

Explain why the early Earth did not form with water, and how it gained it later in its formation.
 
  What will be an ideal response?

[dajones82]

Answer to Question 1

C

Answer to Question 2

Earth, and all terrestrial planets, formed inside the frost line from rocky and metallic planetesimals. The temperature of the solar nebula was too hot for water ice to exist and Earth was too small to hold onto a substantial atmosphere of hot gases. Earth gained its water later during the heavy bombardment phase when water-rich planetesimals that formed beyond the frost line were scattered into the inner solar system, predominantly through gravitational encounters with Jupiter, and impacted Earth.

[daltonest1984]

Thank you!

[dajones82]

Always glad to help...