Final answer:
Stomach bacteria are acidophilic and grow best in highly acidic environments; thus, the optimal pH for bacteria that live in your stomach is A) pH = 1.5.
Step-by-step explanation:
Bacteria Optimal pH Environment
Bacteria that live in your stomach are those that grow best at acidic pH values. Specifically, these bacteria are acidophilic, meaning they thrive in acidic environments. The stomach has a very low pH, which is highly acidic. Based on this understanding, the correct answer is A) pH = 1.5, as this is the only option that falls within the acidic range suitable for stomach bacteria. It's important to note that the majority of bacteria are neutrophiles and grow best at a pH close to neutral pH 7; however, the acidic environment of the stomach favors acidophilic bacteria.
For example, the bacterium Helicobacter pylori is well-adapted to survive and colonize the acidic environment of the stomach. It has developed mechanisms to tolerate the low pH by neutralizing the acid around it. Other bacteria mentioned, such as Escherichia coli and Salmonella spp., are generally neutrophilic and therefore prefer a pH closer to neutral, but some pathogenic strains have evolved acid resistance mechanisms to survive in the stomach.