That both of them are warm....at a certain temputurature causing one to fell,cozy
Answer:
D
Explanation:
D is the answer because 2 is needed to know
Explanation:
1 sugar solution =Distillation
2 Iron powder and sand=magnetic separation
3 petrol and diesel= Fractional distillation
4 Camphor and glass powder = Sublimation
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
