This diagram represents the life track of a 1-solar-mass star.Refer to the life stages labeled with Roman numerals.

-During which stage is the star's energy supplied by primarily by gravitational contraction?
A)II
B)III
C)V
D)VI
E)VII

Question

This diagram represents the life track of a 1-solar-mass star.Refer to the life stages labeled with Roman numerals.
 
-During which stage is the star's energy supplied by primarily by gravitational contraction?
A)II 
B)III 
C)V 
D)VI 
E)VII

Quizplus · Accepted Answer

The energy during stage II (protostar) is primarily supplied by gravitational contraction as the star is still forming and has not yet begun nuclear fusion.

This Diagram Represents the Life Track of a 1-Solar-Mass Star