How many crusades were there and what was thier aims?

Crusades were a series of 9 military expeditions which sought to recapture Jerusalem and other places sacred to Christianity from the Muslims. They were formally launched by Pope Urban II in the late 11th century to help the Byzantine Empire against the Seljuk Turks.

radioactive dating, also known as  radioisotope dating  is a process that in  estimating the approximate  age  of  rocks. these data can be analyzed from  the studies dealing with the  decay of the radioactive elements that are present in these rocks. in nature, there are a few types of materials or atoms which are quite unstable and they spontaneously decay or breakdown to form other kinds of atoms.

the answer is states.