B100 100% neat biodiesel, a renewable, biodegradable fuel. See also: Biodiesel
B20 Blend of biodiesel fuel with 80% petroleumbased diesel and 20% biodiesel. It can be used in diesel vehicles with no modiﬁcations to their engines, fuel systems, or refueling infrastructure. See also: Biodiesel
Background extinction Extinction of species as a result of changes in environmental conditions in an ecosystem.