What changes take place in the nucleus in step 3?
The actinium atom loses a proton and a neutron,
The actinium atom loses two protons and two neutrons.
The actinium atom loses a proton and gains a neutron.
The actinium atom loses a neutron and gains a proton.

firearm identification is the process of analyzing the bullets and cartridge cases left at a crime scene to determine if they came from a particular firearm. marks on the bullets and cartridges may be common to every firearm of that type. these are called class characteristics.