Imagine an advanced civilization living on a planet orbiting at a ...

[jake]

Imagine an advanced civilization living on a planet orbiting at a distance of 10 AU (1.5 billion kilometers) from a close binary star system that consists of a 15 MSun red giant star and a 10 MSun black hole.
 
  The black hole is surrounded by an accretion disk. Sometime within the next million years or so, the civilization's planet is likely to be doomed because A) the red giant will probably supernova within the next million years.
  B) jets of material shot out of the accretion disk will shoot down their planet.
  C) the red giant star, which provides most of energy the civilization needs to exist, will soon be destroyed in the accretion disk.
  D) tidal forces from the black hole will rip the planet apart.

Question 2

What is the difference in meaning between the terms weather and climate?
 
  A) Weather refers to local conditions, and climate refers to global conditions.
  B) Weather refers to short-term variations in conditions, and climate refers to long-term variations in conditions.
  C) Weather refers to small storms, and climate refers to large storms.
  D) Weather refers to wind and rain, and climate refers to processes like convection.
  E) There is no difference between weather and climate.

[Li Jun]

Answer to Question 1

A

Answer to Question 2

B

[jake]

Gracias!

[kishoreddi]

Excellent