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 Mitochondrion Converts Energy from Fuel Molecules into ATP
A signature sequence in the EF-1α/EF-Tu protein family
Regular diesel fuel on the left has a clear or greenish tint, whereas fuel for off-road use is ...
Connect a fuelpressure gauge to the fuel rail at the Schrader valve.
Mass spectrometry (MS) for Mass, Sequence, and Amino Acid Analyses of Purified Proteins
How to calculate fuel costs