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.
The conduction system of the heart; traces the path of the electrical impulse that stimulates the he
Diesel combustion occurs when fuel is injected into the hot, highly compressed air in the cylinder.
A dim headlight indicates excessive resistance in fuel pump circuit.
A dual-nozzle TBI unit on a Chevrolet 5.0 L V-8 engine. The fuel is squirted above the throttle ...
Three Main Types of Tectonic Plates Boundaries
Opener Alignment comparing DNA sequence for the leptin gene from dogs (top) and humans (bottom)