Answer:
the exposed core of a dead star, supported by electron degeneracy pressure.
Explanation:
A white dwarf is a low luminosity exposed core of a dead star having mass comparable to the sun but volume comparable to the earth . So its density is very high . These stars have lost the capacity to generate energy through the process of fusion . Due to high gravitational energy , it goes on shrinking but ultimately balanced by electron degeneracy pressure. It is not a main sequence star as it has lost the power of fusion .
Let say the two train cars are of masses
and 
now if the speed of two cars are
and 
then we can say that the momentum of two cars before they collide is given by

here two cars are moving in opposite direction so we can say that the net momentum is subtraction of two cars momentum.
Now since in these two car motion there is no external force on them while they collide
So the momentum of two cars are always conserved.
hence we can say that the final momentum of two cars will be same after collision as it is before collision

Answer:
An object may become extinct due to the lack of quantity of the object and the object no longer exists so it is now extinct.
Answer:
B convection MERRY CHRISTMAS
Explanation:
Answer:
B. 161.5 J
Explanation:
= Number of moles = 0.37
= Rise in the temperature of the oxygen gas = 15 K
= heat added in order to raise the temperature
= specific heat at constant pressure = 3.5
At constant pressure, heat is given as
