How can we search for evidence that other planets were once habitable

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.

If element x has 99 protons how many electrons does it have

Acoil suspended freely, points in some direction when no current is passed through it . can you tell what will happen when a current is passed though it?