Compounds that have the same molecular formula but different chemical structures are called isomers. Remember isomerism is a property between a pair (or more) of molecules, i.e. a molecule is an isomer of another molecule. A similar relationship is that of brother or sister...
Many Americans are up in arms. But in fact, keeping out desperate souls seeking entry into America has deep roots. On this day 100 years ago, the United States passed the strictest immigration law of its time: the Immigration Act of 1917. The law restricted the immigration of undesirables, including many people from the Middle East and Asia, through increased taxes, tests and outright bans.
Another restriction that was lifted as a result of the enacted United States immigration law was restrictions against immigrants that are HIV-positive. The Immigration Act of 1990 is considered to be one of the most considerable changes to United States immigration law since 1965.