1. Multiple Choice: Which of the following microorganisms is known to be acid-fast? a) Escherichia coli b) Staphylococcus aureus c) Mycobacterium tuberculosis d) Pseudomonas aeruginosa Correct Answer: c) Mycobacterium tuberculosis Rationale: Mycobacterium tuberculosis has a waxy cell wall that retains certain stains even after being washed with acid alcohol, which is the basis of the acid-fast staining technique. 2. True/False: Endospores are a reproductive structure in bacteria. Answer: False Rationale: Endospores are not used for reproduction but are a survival mechanism for bacteria, allowing them to withstand harsh environmental conditions. 3. Fill-in-the-Blank: The process b