Aren't these things which you could find easily in a textbook? Basically, sporulation creates spores which are very resilient and can survive in conditions that would kill a bacteria (e.g. extreme heat or cold, low moisture). However, spores won't replicate so if a bacteria were to sporulate during conditions conducive to growth, it would be at a disadvantage because it could not take advantage of the favorable conditions by reproducing.
Obligate anaerobes do not prefer oxygen! Obligate anaerobes use anaerobic respiration only and die in the presence of oxygen because they lack the enzymes to deal with radical oxygen species. Faculative anaerobes contain the cellular machinery for both anaerobic and aerobic respiration and thus can survive in the presence and absence of oxygen.