Bacteria - A large group of unicellular microorganisms that lack a cell nucleus. Some bacteria are pathogenic and harmful to humans, some have no effect at all on humans, and some are beneficial.⏎
Chromosome - An organized structure of DNA and proteins within the nucleus of a cell that contains many genes.⏎
Adaptive Mutation - A mechanism through which certain cells can increase the rate in which genetic mutations occur, often in response to stress. This mechanism may help explain how bacteria develop resistance to certain antibiotics.⏎
Bronchial Tubes - Large tubes that carry air into smaller branches of the lungs after the air has passed through the mouth, nasal passages, and windpipe.⏎
Cancer - A class of diseases in which abnormal cells divide without control and are able to invade healthy tissues in various parts of the body.⏎