1. diagnostic imaging - X-Rays, CT Scans and MRI's, reveal internal structures hidden by the skin and bones,to help diagnose and treat disease, as well as identify abnormalities.
2. nuclear fission - a nuclear reaction in which a heavy nucleus splits spontaneously or on impact with another particle, with the release of energy.
3. nuclear fusion - a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy.
4. hydrocarbons - a compound of hydrogen and carbon, such as any of those which are the chief components of petroleum and natural gas.
5. stem cells - an undifferentiated cell of a multicellular organism which is capable of giving rise to indefinitely more cells of the same type, and from which certain other kinds of cell arise by differentiation.
6. tissue engineering - is the study of the growth of new connective tissues, or organs, from cells and a collagenous scaffold to produce a fully functional organ for implantation back into the donor host.
7. asteroid - a small rocky body orbiting the sun. Large numbers of these, ranging enormously in size, are found between the orbits of Mars and Jupiter, though some have more eccentric orbits.
8. meteor - a small body of matter from outer space that enters the earth's atmosphere, becoming incandescent as a result of friction and appearing as a streak of light.
9. ecosystem - a biological community of interacting organisms and their physical environment.
10. biosphere - the regions of the surface and atmosphere of the earth or another planet occupied by living organisms.
11. hydrosphere - all the waters on the earth's surface, such as lakes and seas, and sometimes including water over the earth's surface, such as clouds.