Edexcel IGCSE Biology Revision new 2022 best exam reviews solution

Active Transport - When a substance moves against/up a concentration gradient, from a region where they are of lower concentration to a region where they are of higher concentration. Adaption - Any characteristic of an organism that improves its chances of surviving in its environment. Aerobic respiration - Respiration with oxygen. Anaerobic respiration - Respiration without oxygen. It releases less energy than aerobic respiration. Alleles - Different forms of a gene which occupy the same relative positions on a pair of homologous chromosomes. Arteries - Blood vessels which carry blood away from the heart. Anaesthetics - Drugs that make the body unable to feel pain. Artificial selection - A method used by humans to produce plants and animals with desired qualities. Natural selection - When organisms better adapted to their environment tend to survive and produce more offspring. Asexual reproduction - The process resulting in the production of genetically identical offspring from one parent, without the fusion of gametes. Assimilation - The process whereby some of the absorbed food materials are converted into new protoplasm or used to provide energy. Breathing - The process that brings about an exchange of gases between an organism and its environment. Ventilation - The inhalation and exhalation of air