Approximately how old are the erosion channels seen on the ...

[saliriagwu]

Approximately how old are the erosion channels seen on the surface of Mars?
 
  A) 3 billion years
  B) 4.6 billion years
  C) 1 billion years
  D) 500 million years

Question 2

How many forces operated in the universe during the GUT era?
 
  A) one, what we call the super force
  B) two, gravity and the GUT force
  C) two, gravity and the electroweak force
  D) three, gravity, the strong force, and the electroweak force
  E) all of the above forces

[pami445]

Answer to Question 1

A

Answer to Question 2

B