a stable subatomic particle with a charge of negative electricity, found orbiting the nucleus of an atom
symbiosis that is beneficial to both organisms involved
the name given to a horizontal row of the periodic table
A disease that has spread over a whole country or the world
the rigid outer part of the earth, consisting of the crust and upper mantle
an organism, either a green plant or bacterium, which is part of the first level of a food chain
The substance that is dissolved in a solution
each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties
the youngest layer is on top and the oldest on bottom, each layer being younger than the one beneath it and older than the one above it
repair and growth; a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth
the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock
the process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth
The role or function of an organism or species in an ecosystem
has mass and takes up space
The sudden start of a disease
physical rather than biological; not derived from living organisms
fatty acids that include many natural oils, waxes, and steroids
any of a group of unicellular, multicellular, or syncytial spore-producing organisms feeding on organic matter, including molds, yeast, mushrooms, and toadstool
A substance used to stimulate the production of antibodies and provide immunity against one or several diseases, prepared from the causative agent of a disease, its products, or a synthetic substitute, treated to act as an antigen without inducing the disease