Bree Wakefield is a 19 year old college student, living in a dormitory on the campus of her university. She started to feel poorly and began to miss classes. She was diagnosed with a disease of the CNS ?

Which of the following correctly describes what happens when an atomic bomb explodes? small pieces of fissionable material are joined and form a body with a mass greater than the critical mass, the relative number of neutrons escaping decreases, and a chain reaction and explosion result. large pieces of fissionable matter are brought together quickly and form a body with a mass smaller than the critical mass, the relative number of escaping neutrons increases, and a chain reaction and explosion result.