You inoculated a pure culture of unknown bacteria into a tube containing thioglycollate medium to study their metabolic relationship with oxygen. The culture was incubated for an appropriate length of time at the optimal growth temperature of the organism. When you examined the culture, you observed that although the organism grew throughout the medium, the growth was denser at the surface. What would you conclude about the oxygen requirements for this unknown species?

Facultative anaerobic bacteria is distinct out of the rest bacteria due to the fact that they can strive in the presence or absence of oxygen due to its versatile attributes. A few are known as causative organism for infections in humans.

Facultative anaerobes have optimal growth in the availability of oxygen as it produces 38 molecules of ATP from its aerobic respiration but can strive and grow (no optimal growth) to yield around 2 molecules of ATP.

Examples are pathogens, or microbes that leads to disease. Such as Salmonella species, Shigella, and Escherichia coli (E. coli) which are well known for its infection on the digestive system.

i believe the answer would be b. hope it : )

the correct answer is 2 and 4