The fact that the life on Earth seems to have appeared quite ...

[tingc95]

The fact that the life on Earth seems to have appeared quite rapidly suggests that life
 
  A) can arise on most habitable worlds
  B) can only appear soon after a planet forms
  C) on any kind of planet is inevitable
  D) is only possible on Earth-like planets

Question 2

Suppose we observe a source of X-rays that varies substantially in brightness over a period of a few days. What can we conclude?
 
  A) The X-ray source is a quasar.
  B) The X-ray source contains a black hole with an accretion disk.
  C) The X-ray source is no more than a few light-days in diameter.
  D) The X-ray source must have a strong, rapidly varying magnetic field.
  E) We are seeing the rapid orbit of two stars in a binary system.

[jamesnevil303]

Answer to Question 1

A

Answer to Question 2

C

[tingc95]

Gracias!

[kilada]

Excellent