Short answers, pulled from the story.
Bacteria emerged approximately 4 billion years ago as the first life forms to appear on Earth. They existed as the sole architects of the planet's early biosphere for three billion years before more complex organisms arose.
Thiomargarita magnifica can grow up to 2 centimetres in length, which is 50 times larger than other known bacteria. This species is visible to the unaided eye, unlike most bacteria that measure between 0.5 and 5.0 micrometres.
There are an estimated 43,000 named species of bacteria, yet the vast majority have never been studied by science. Just 10 bacterial species account for half of all publications while nearly 75% of all named bacteria have no academic research devoted to them.
Endospores are highly resistant, dormant structures formed by certain genera of Gram-positive bacteria such as Bacillus and Clostridium. These structures contain a core of DNA and ribosomes protected by a multilayer rigid coat, allowing bacteria to survive extreme physical and chemical stresses including heat, freezing, radiation, and the vacuum of outer space.
Clostridium tetani endospores cause tetanus when they contaminate deep puncture wounds, while Bacillus anthracis endospores cause anthrax when inhaled. Both species belong to genera capable of forming highly resistant endospores that allow them to survive extreme conditions.