1) While the concept of zombies created by God or supernatural means is unlikely, a zombie apocalypse caused by a biological agent such as a virus is more plausible according to the document. 2) A dormant or mutated virus could potentially spread quickly through the population like the flu and turn people into zombies. 3) An outbreak of infected living people displaying zombie-like behaviors (called "pseudo-zombies") may be even more likely than an uprising of reanimated corpses.