If you're looking for "what rocks are formed by changes..." it's Igneous Rocks.
Answer:
Chemical energy obtained from the breakdown of food molecules.
Answer:
Kb = 
Explanation:
For a weak organic base, the formula to find 
is given by:
where c is the concentration of base.
Here c= 
Substituting the above values in the formula,we get:
Hence:
Kb =
Since we're talking about a chain reaction, I think this would be a) self-sustaining. Chain reactions are not usually described as "weak" and can be highly explosive depending upon the compounds (think Uranium!).
The first (artificial) self-sustaining nuclear reaction is attributed to Enrico Fermi in 1942. Here's a bit of history:
http://www.atomicarchive.com/History/firstpile/firstpile_01.shtml
