John Calhoun's defense of slavery was known as

on this day in 1833, president andrew jackson announces that the government will no longer use the second bank of the united states, the country's national bank. a national bank had first been created by george washington and alexander hamilton in 1791 to serve as a central repository for federal fund

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.