Which of the following best explains why there is no growth on Plate II in a microbiology experiment?

• A. The medium on Plate II lacks essential nutrients required for microbial growth.
• B. Plate II was incubated at the optimal temperature for microbial growth.
• C. Plate II was inoculated with a high concentration of bacteria.
• D. The pH of the medium on Plate II was adjusted to neutral.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the conditions required for microbial growth, which typically include the presence of essential nutrients, appropriate temperature, suitable pH, and absence of inhibitory substances.
2. Step 2: Analyze the given options to identify which factor directly affects the ability of microbes to grow on the medium. Consider that optimal temperature and neutral pH generally support growth, and a high concentration of bacteria should not prevent growth.
3. Step 3: Recognize that the absence of growth on Plate II despite optimal temperature and neutral pH suggests a lack of essential nutrients in the medium, which are critical for microbial metabolism and reproduction.
4. Step 4: Recall that essential nutrients include carbon sources, nitrogen, vitamins, and minerals necessary for cellular functions, and without these, microbes cannot synthesize vital components or generate energy.
5. Step 5: Conclude that the best explanation for no growth on Plate II is that the medium lacks these essential nutrients, preventing microbial proliferation despite other favorable conditions.