Transition Zone - The area, sometimes referred to as an ecotone, encompassing the edges of two distinct ecosystems, such as the area where a forest intersects with grassland.⏎
White Blood Cell - A special type of cell that works as part of the immune system to defend the body against disease and infection.⏎
Sperm Cell - The male gamete, or sex cell, which carries the hereditary material of the male parent and unites with the female egg cell during sexual reproduction.⏎
Vector - An organism (usually an arthropod such as a flea, mosquito, or tick) that carries an infectious agent from one host to another.⏎
Species - One of the most basic units of biological classification, ranking just below the genus and comprising individuals or populations capable of interbreeding.⏎