Fertilized Egg - Sometimes referred to as a zygote, this is the resulting initial cell formed when a sperm cell unites with an egg cell.⏎
Contagion - A general term for any disease-causing infectious agent spread by direct or indirect contact.⏎
Gastrointestinal Tract - The structure in the body, beginning with the mouth and extending to the anus, through which food is ingested, broken down, and absorbed to provide the body with nutrients, and waste products are excreted.⏎
Fungi - A taxonomic kingdom of spore-forming organisms distinct from plants, animals, and bacteria that includes microorganisms such as yeast and molds, as well as mushrooms.⏎
Exoskeleton - An external skeleton that protects and supports an organism, in contrast to an internal endoskeleton.⏎