| A | B |
|---|
| Abiotic | the non-living component of an ecosystem |
| Absorption | movement of digested food molecules into the bloodstream |
| Active site | the part of the enzyme that binds an enzyme to its substrate molecule |
| ADH | hormone that causes water retention in the kidney |
| Aerobis Respiration | release of energy from food in the presence of oxygen |
| Allele | alternative version of a gene |
| Alveolus | air sac found at the end of the bronchioles |
| Anabolism | the chemical build-up of complex substances requiring energy |
| Antagonistic muscles | muscles that have opposite effects to one another |
| Apical dominance | the suppression of the growth of lateral buds by the terminal bud |
| Bile | fluid produced by the liver |
| Binary fission | a form of asexual reproduction |
| Biology | the study of living things |
| Biomass | the amount of living matter present at any level in a food chain. |
| Biosphere | the part of the earth and its atmosphere in which life can occur |
| Blind spot | the part of the retina where the nerves leave the eye |
| Biotic | the living part of an ecosystem |
| Bladder | holds the urine produced by the kidneys |
| Blood vessel | tube for transporting blood |
| Behaviour | the response of an organism to changes in its environment |
