Why do some scientists think that Jupiter's existence may have ...

[Garrulous]

Why do some scientists think that Jupiter's existence may have been critical for life to evolve on Earth?
 
  A) It prevented Earth from migrating outward and thus ensured a stable climate.
  B) It prevented Earth from migrating inward and thus ensured a stable climate.
  C) It kicked out many comets from the inner solar system through gravitational encounters, thus limiting the number of objects that could potentially hit the inner planets.
  D) Meteorites from Jupiter may contain bacteria that started life on Earth.
  E) It stabilized Earth's axis tilt and thus ensured a stable climate.

Question 2

Density waves may explain
 
  A) the lack of blue stars in the halo.
  B) the random orbits of halo stars.
  C) the density of red stars in the bulge.
  D) the spiral arm structure of the Galaxy.
  E) the large number of open clusters in the halo.

[iceage]

Answer to Question 1

C

Answer to Question 2

D

[Garrulous]

Excellent

[Jossy]

TYSM