Alexander Fleming while working on ………..bacteria , observed Penicillium notatum growing in one of his unwashed culture plates around which these bacteria could not grow.

Options

A. Streptococci
B. Diplococci
C. Staphylococci
D. Streptobacilli

Answer

**Step-by-Step Solution:**

1. **Understanding the Context**: Alexander Fleming was a scientist known for his discovery of penicillin, which is an antibiotic. This discovery was made while he was working with bacteria.

2. **Identifying the Bacteria**: The question asks which type of bacteria Fleming was working on when he made his observation. The options provided include Stryptococci, Diplococci, Staphylococci, and Stryptobacillus.

3. **Fleming's Experiment**: In his experiment, Fleming noted that around the mold Penicillium notatum, there was an area where bacteria could not grow. This indicated that the mold was producing a substance that inhibited bacterial growth.

4. **Determining the Correct Bacteria**: The specific bacteria that Fleming was working with at that time was Staphylococci. This is the bacteria that was affected by the penicillin produced by the mold.

5. **Conclusion**: Therefore, the correct answer to the question is Staphylococci.

**Final Answer**: Alexander Fleming was working on **Staphylococci** bacteria.

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