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.
Radioactive contamination and radiation exposure could occur if radioactive materials are released into the environment as the result of an accident, an event in nature, or an act of terrorism. Such a release could expose people and contaminate their surroundings and personal property.
Methane is released into the atmosphere by both natural and anthropogenic sources. It is released in low oxygen environments such as swamps and bogs and through the roots of some plants. Anthropogenic sources have increased methane emissions through increased use of natural gas and through mining.