The heavy bombardment phase of the solar system lasted :

The heavy bombardment phase of the solar system lasted
 
  A) several million years.
  B) several tens of millions of years.
  C) several hundreds of millions of years.
  D) about a billion years.
  E) to the present time.

Question 2

The plane in which almost all planets orbit the Sun is called the
 
  A) equator of the solar system.
  B) ecliptic.
  C) equant.
  D) node.
  E) galactic plane.

Question 3

The solar magnetic field is strongest in those regions called ________, which are poles and usually thus occur in pairs.
 
  Fill in the blank(s) with correct word