any specific behavior | the act of spreading outward from a central source |
the trait of being active; moving or acting rapidly and energetically | (medicine) the treatment of disease (especially cancer) by exposure to a radioactive substance |
an organic process that takes place in the body | a radial arrangement of nerve fibers connecting different parts of the brain |
a process existing in or produced by nature (rather than by the intent of human beings) | the spread of a group of organisms into new habitats |
the state of being active | energy that is radiated or transmitted in the form of rays or waves or particles |
(chemistry) the capacity of a substance to take part in a chemical reaction | the spontaneous emission of a stream of particles or electromagnetic rays in nuclear decay |
| syndrome resulting from exposure to ionizing radiation (e.g., exposure to radioactive chemicals or to nuclear explosions); low doses cause diarrhea and nausea and vomiting and sometimes loss of hair; greater exposure can cause sterility and cataracts and some forms of cancer and other diseases; severe exposure can cause death within hours |