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.
Natural sources of background radiation include: 1  Cosmic rays-radiation that reaches the Earth from space. 2  Rocks and soil-some rocks are radioactive and give off radioactive radon gas.atural sources. Natural sources of background radiation include: 1  Cosmic rays-radiation that reaches the Earth from space. 2  Rocks and soil-some rocks are radioactive and give off radioactive radon gas. 3  Living things-plants absorb radioactive materials from the soil and these pass up the food chain.