The core of a protostar that will eventually become a brown dwarf ...

[gbarreiro]

The core of a protostar that will eventually become a brown dwarf shrinks until
 
  A) the type of pressure called degeneracy pressure becomes important.
  B) its central temperature is high enough to support fusion reactions.
  C) it forms a rocky core.
  D) it radiates brown light.

Question 2

Which hemisphere on Mars is believed to be older, and what is the evidence?
 
  What will be an ideal response?

[Cheesycrackers]

Answer to Question 1

A

Answer to Question 2

The southern hemisphere is older and higher in elevation, since it has more impact craters, while the northern shows more recent volcanism and lava flows, and even ocean basins over much of the low region near the north pole.

[gbarreiro]

TYSM

[kjohnson]

Gracias!