Contagion - A general term for any disease-causing infectious agent spread by direct or indirect contact.⏎
Gene - The physical and functional unit of heredity made up of DNA. Every individual has two copies of each gene, one inherited from the mother and the other from the father.⏎
Egg Cell - The female gamete, or sex cell, which carries the hereditary material of the female parent and unites with the male sperm cell during sexual reproduction.⏎
Epidemic - An often sudden increase in the level of disease in a specific population over a given period of time.⏎