ANTIBIOTIC SUSCEPTIBILITY TESTING. Bacteria demonstrate two kinds of resistance to antibiotics, namely intrinsic resistance and acquired resistance. Intrinsic resistance means that the species was resistant to an antibiotic even before its introduction.
Radiation is naturally present in our environment, as it has been since before the birth of this planet. In addition, radiation can be produced artificially, as in medical x-rays and microwaves for cooking. Nonetheless, most people are not aware of all the natural and man-made sources of radiation in our environment.
At Three Mile Island and Chernobyl, nuclear power plants released radioactive substances into the atmosphere during nuclear accidents. And in the aftermath of the March 2011 earthquake and tsunami that struck Japan, a nuclear crisis raised fears about radiation and questions about the safety of nuclear power.