Answer : 1. "Bacteria"
Explanation :

Recently researchers have unveiled the mitochondrial Coxiella effector F (MceF), an antioxidant protein produced by the gram-negative intracellular bacterium Coxiella burnetii. MceF supports human cell health despite heavy bacterial load. Upon invading host cells, Coxiella burnetii releases MceF interacting with glutathione peroxidase 4 (GPX4) in the mitochondria. This interaction enhances mitochondrial function, preventing cell damage and death associated with pathogen replication in mammalian cells. The newly discovered protein shows potential therapeutic applications.