Answer to Question 1
Hydrogen.
Answer to Question 2
Once the usable hydrogen fuel is all burned up, there remains a helium-rich core. Once fusion is finished in the star's core, there is insufficient pressure to prevent collapse due to gravity, and the contraction generates a huge increase in internal temperature, triggering a higher level of hydrogen fusion in the star's shell. The outer shell expands from the heat of accelerated fusion, but this expansion simultaneously cools the star's surface, yielding a large, cool star.
A schematic showing that an inertia switch is connected in series between the fuel-pump relay and ...
Checking fuel-pump volume using a hose from the outlet of the fuel-pressure regulator into a ...
To check to see if the electric fuel pump can be operated from the relay contacts, use a fused ...
Natural gas is a cleaner fuel than coal
The Main Macromolecules in Cells
The lacO region O1 containing an inverted repeat sequence