Organism - A living being that can reproduce, grow, react to external stimuli, and maintain its internal equilibrium.⏎
Natural Selection - The process by which certain heritable traits that contribute to the survival and reproductive success of an organism become more widespread within a population over successive generations.⏎
Reproduction - The process by which parent organisms create new offspring by either sexual or asexual means.⏎
Respiratory Tract - The part of the anatomy that has to do with the passage of air and includes the nose, larynx, trachea, and lungs.⏎