| A | B |
|---|
| Bacteria | part of a classification system that divides all living things into six kingdoms Kingdom Bacteria includes microscopic single-celled organisms found in many environments bacteria can be associated with disease in other organisms |
| Bacteria of decay | microorganisms that break down dead organisms and return nutrients to the environment |
| Bar graph | visual tool used to organize illustrate and compare observations |
| Barometer | an instrument that measures air pressure in the atmosphere |
| Barrier island | a long narrow island that develops parallel to a coast as a sandbar builds up above the water’s surface |
| Base | a substance that can accept a proton from another substance and has a pH above 7 |
| Behavior | an organism’s action in response to a stimulus |
| Bernoulli’s principle | a statement that describes the effects of movement on fluid pressure an increase in the speed of the motion of a fluid decreases the pressure within the fluid |
| Big bang | according to scientific theory the moment in time when the universe started and began to expand |
| Binary code | a coding system in which information is represented by two figures |
| Binary fission | a form of asexual reproduction by which some single-celled organisms reproduce the genetic material is copied and one cell divides into two independent cells that are each a copy of the original cell prokaryotes such as bacteria reproduce by binary fission |
| Binomial nomenclature | the two-part naming system used to identify species the first part of the name is the genus and the second part of the name is the species |
| Biodiversity | describes the great variety of species on earth or within a habitat |
| Biology | the scientific study of life and all living things |
| Bioluminescence | the production of light by living organisms |
| Biomass | organic matter that contains stored energy from sunlight and that can be burned as fuel |
| Biome | a region of Earth that has a particular climate and certain types of plants |
| Biosphere | all living organisms on Earth in the air on the land and in the waters one of the four parts of the Earth system |
| Biotic factor | a living thing in an ecosystem |
| Black hole | the final stage of an extremely massive star which is invisible because its gravity prevents any form of radiation from escaping |
| Blizzard | a blinding snowstorm with winds of at least 56 kilometers per hour (35 miles/hour) |
| Blood | a fluid in the body that delivers oxygen and other materials to cells and removes carbon dioxide and other wastes |
| Blubber | a layer of fat in some sea mammals that lies beneath the skin it insulates the animal from cold and stores reserve energy |
| Boiling | the rapid change in phase from liquid to gas |
| Boiling point | the temperature at which a substance changes rapidly from a liquid to gas |
| Bond energy | the amount of energy in a chemical bond between atoms |
| Budding | a process of asexual reproduction in which an organism develops an outgrowth of the parent each bud can grow into a new organism breaking free and becoming separate and independent |
| Buoyancy | the tendancy of an object to float |
| Buoyant force | the upward force on objects in a fluid |
