What do extremely massive stars end their life as?
A) Red Supergiants
B) White Dwarves
C) Protostars
D) Black Holes

The difference between two numbers is 15. when twice the smaller number is subtracted from three times the larger number, the difference is 58.what is the larger number?

Two vectors are shown. which statement best compares the vectors? vector x has greater magnitude than vector y. vector y has greater magnitude than vector x. the vectors have the same displacement. the vectors have the same direction.

Ammonia enters the expansion valve of a refrigeration system at a pressure of 10 bar and a temperature of 18oc and exits at 6.0 bar. the refrigerant undergoes a throttling process. determine the temperature, in oc, and the quality of the refrigerant at the exit of the expansion valve.