Note: 1,000 career games played are needed to make this list of the one-thousand greatest on base plus slugging leaders, raw averages are presented in parenthesis to further distinguish the top one-hundred, and a bold faced entry denotes that the player was active during the previous Major League season.
Primary active transport, directly uses metabolic energy (ATP) to transport molecules across a membrane.
Active shooter. Active killer or active shooter names the perpetrator of a type of mass murder marked by rapidity, scale, randomness, and often suicide. The United States Department of Homeland Security defines the active shooter as an individual actively engaged in killing or attempting to kill people in a confined and populated area; in most cases, active shooters use firearms and there is no pattern or method to their selection of victims. Most incidents occur at locations in which the killers find little