[5]Nuclides is a term used to describe all the forms of all the atoms. Radionuclides are radioactive nuclides.
[6]An ecosystem is a natural community, taken as a whole, including all biological and environmental factors.
[7]Ecologists are scientists concerned with the interrelations of organisms and their environments.
[8]A thermonuclear device is an explosive, such as a hydrogen bomb, based on a fusion reaction. In other atomic weapons the energy is derived from nuclear fission.
[9]The living organisms.
[10]Plankton are the floating, minute plants and animals that live in the sea (and also in fresh water), including diatoms, algae, protozoans, and crustaceans.
[11]For more on this program, see Plowshare, a companion booklet in this series.
[12]The half-life of a radioactive element is the time required for half its atoms to lose their radioactivity.
[13]Atmospheric tests of nuclear weapons through 1962 produced a fission yield equivalent to 191 million tons of TNT and introduced about 10.01 megacuries of strontium-90, for example, as fallout entering the environment.
[14]Floating one-celled animals.