Which of these is the likely progenitor of a type II supernova? ...

[nenivikky]

Which of these is the likely progenitor of a type II supernova?
 
  A) a mass-transfer binary, with the white dwarf already at 1.3 solar masses
  B) a contact binary, with the neutron star at 2.3 solar masses
  C) an evolved red giant which is just starting to make silicon in its core
  D) two white dwarfs in a contact binary system
  E) an evolved blue supergiant that is about to experience the helium flash

Question 2

How did Alfred Wegener first notice the possibility of plate tectonics? What lies in the gap he noted?
 
  What will be an ideal response?

[bigcheese9]

Answer to Question 1

C

Answer to Question 2

He found that the western coast of Africa was an almost perfect fit for the eastern coast of South America. We now know the Mid-Atlantic Rift sits between them and its expansion is causing them to continue separating with time.

[nenivikky]

Great answer, keep it coming

[amcvicar]

TYSM