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absolute zero

the lowest possible temperature, about -273 degrees Celsius


a substance that forms hydronium ions in water; having a pH less than 7

acid rain

rain made acid by absorbing sulfur and nitrogen oxides from polluted air


a hormone of the adrenal gland, secreted in times of emergency

air mass

a large body of air characterized by certain values of temperature and humidity


simple, green organisms with cell walls, but without the complex structure of plants


a strongly basic hydroxide


a substance composed of two or more metals

alternating current

an electric current that reverses direction periodically

amino acid

organic chemicals with an acid group (-COOH) at one end and an amino group (-NH2) at the other; the constituent molecules of proteins


substandard concentration of red blood cells


a blood protein that protects the body from foreign chemicals or microorganisms


the largest artery, carrying blood out of the left ventricle


a muscular-walled blood vessel that distributes blood to the body tissues


the layer of air surrounding the earth


the smallest part of an element


the smallest and simplest one-celled organisms, having neither nucleus nor other organelles


an instrument for measuring atmospheric pressure


the solid rock underlying the loose material at the earth's surface

boiling point

the temperature at which, at any given pressure, the liquid and gas phases of a substance are in equilibrium


a quantity of heat energy, equal to 4.185 joules; the Large Calorie of the nutritionist is a kilocalorie, equal to 1000 calories


1) a thin tube into which water can rise by adhesion to the surface 2) a tiny blood vessel connecting an artery to a vein and providing interchange of materials between blood and tissue


a substance that increases the rate of a chemical reaction without being used up in the reaction

chemical formula

conventional representation of the atomic composition of a compound

chemical reaction

a process in which the molecules or ionic composition of one or more substances is altered


the large intestine


the amount of a substance contained in a given volume of a solution or other mixture


a material through which heat or electrical current may pass


the process of enzymatic breakdown of large organic molecules into smaller, soluble ones

dilute solution

a solution in which the solute has a low concentration


deoxyribose nucleic acid, the substance of the genes

ductless gland

an endocrine organ


the study of the relationships between organisms and with their inorganic environment

electric charge

the property of particles (such as electrons and protons) by which they exert forces on each other without respect to their mass

electric current

a flow of electric charge, typically carried by electrons through a metal or by ions through a solution or a plasma

electromagnetic waves

disturbances in electric and magnetic fields propagating through space


a particle found in all atoms, having a small mass and a single unit of negative electric charge

electrostatic force

the force particles exert on each other because of their electric charge


a substance consisting of only one species of atom, so that it cannot be decomposed by chemical means


an organism in the earliest stages of its development

endocrine organ

a gland that secretes hormones into the blood


a physical quantity having the dimension of work and measured in joules, whose total quantity remains constant through all interactions and transformations


a substance, usually a protein, produced by living cells and acting as a catalyst


the point on the earth's surface directly above the geological shift that causes an earthquake


the movement of rock, sand, etc., due to natural forces


the tube that carries food from the mouth to the stomach; gullet


conversion of a liquid into the gaseous phase by escape of molecules from the surface


the process by which species undergo drastic changes over long periods of time


the disposal of metabolic wastes from the body, as by urination


a crack in the earth's crust, along which crustal movement takes place


an enzyme-controlled reaction that takes place in the absence of oxygen, such as the conversion of sugar to alcohol by the action of yeast


1) the process of applying nutrients to the soil to stimulate plant growth 2) the union of a sperm and an egg cell to form a zygote


1) reproduction of a one-celled organism by splitting into two equal parts 2) the splitting of an atomic nucleus into approximately equal parts, with the release of energy

flood plain

the flat region around an old river, which becomes covered with water at times of high runoff

food chain

an array of organisms in which each serves as food for the one above


the preserved remains or casts of a long-extinct organism


the number of cycles completed in a unit time in any cyclic phenomenon, such as a vibration


the boundary between two air masses


1) the melting of a solid 2) a nuclear reaction in which two small nuclei combine to form a larger one, accompanied by the release of energy 3) the union of isogametes of one-celled organisms


an agglomeration of many millions of stars


a sex cell, such as egg or sperm


a substance, usually of very low density, that has no surfaces of its own but will spread to fill its container


the particle that carries hereditary info from one generation to another and controls the production of proteins in a living cell


the study of biological inheritance


a large mass of ice moving down a valley or across a continent


the simple sugar that forms the fundamental energy supply of all nucleated organisms


the mass-dependent force by which any two objects in the universe attract each other

greenhouse effect

the warming of the earth resulting from atmospheric gases trapping heat that reradiates from the earth's surface


the part of an ecosystem that is occupied by a given organism


energy that passes from one system to another because of a difference in temperature


a spiral shaped like a spring, characteristics of the DNA molecule


an animal that eats plants only (what Hibari hates the most)


a substance, secreted into the blood by an endocrine gland, that controls chemical processes in other parts of the body


the amount of water vapor in the air

igneous rock

rock formed by the hardening of liquid rock emerging from deep within the earth, either to the surface or within the crust


the property of objects to remain in a state of rest or uniform motion in a straight line unless acted on by an outside force

infrared rays

electromagnetic waves of wavelength longer than those of visible light, but shorter than microwaves


a substance that blocks the passage of heat or electric current


a hormone, produced in the pancreas, that controls the metabolism of glucose


an atom or group of atoms that has acquired either a positive charge or a negative charge by gaining/losing electrons


a line on a weather map connecting points of equal barometric pressure


a variety of an element distinguished by its atomic mass number, but having the same atomic number as all other isotopes of the element

jet stream

a rapidly flowing mass of air high in the atmosphere

Kelvin scale

the SI temperature scale, which has its zero at the absolute zero of temperature

kinetic energy

the energy of an object as measured by its mass and velocity

latent heat

the heat added or removed from a substance that produces a change of phase with no change in temperature


the distance north or south of the equator measured in degrees

light year

the distance light travels in a year


a substance that takes the shape of its container, up to a definite upper surface


a unit of volume equal to 1000 cubic cm


the distance east or west of the prime meridian, measured in degrees

lunar eclipse

condition in which the earth comes between the sun and the moon so that the moon is in the earth's shadow


a device made of a ferromagnetic material, such as steel, which can exert forces on other such materials


the excess force exerted on each other by charges in motion


the quantity of substance in an object measured either by its acceleration when a force is applied or by its gravitational attraction to other objects


the change of matter from solid to liquid

melting point

the temperature at which the solid and liquid phases of a substance can exist in equilibrium


an earth substance with specified chemical constitution


a particle consisting of one or more atoms bound together, and comprising the smallest quantity of a non-ionic substance


an organ that controls body functions by carrying electrochemical impulses

natural selection

the tendency of individuals or species best adapted to a particular environment to leave larger numbers of offspring


an organ that controls body functions by carrying electrochemical impulses


a nerve cell


a neutral particle that is part of the nuclei of atoms, with mass slightly larger than that of a proton


a gaseous element that makes up 79 percent of the atmosphere


1) the massive, charged center of an atom, composed of protons and neutrons 2) a structure in a cell, surrounded by a membrane and containing the chromosomes 3) a particle of dust in the atmosphere around which water condenses, forming a raindrop

organic compound

a molecular chemical compound based on carbon


the diffusion of water through a membrane


the part of the bedrock protruding through overlying sediments


in animals, an organ that produces egg cells; part of the stigma of a flower that contains the ovules


a device for measuring temperature


a poisonous substance produced by bacteria


a material used to induce immunity to a specific disease


the bones that are arrayed linearly to form the back-bone of vertebrates


a submicroscopic particle that can become self-reproducing inside a living cell


the unit of measure of electric potential difference, which provides the condition for the flow of an electric current


the gravitational force that the earth or other astronomical object exerts on an object near its surface


electromagnetic radiation of wavelength shorter than ultraviolet


a cell formed by the fusion of two gametes

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