1. What is the primary role of neutrophils in bacterial infections? A. Production of antibodies B. Phagocytosis of bacteria C. Release of histamine D. Cell-mediated immunity Answer: B. Phagocytosis of bacteria Rationale: Neutrophils are a type of white blood cell that are crucial in the body's defense against bacterial infections. They are primarily responsible for the phagocytosis of bacteria, which involves engulfing and digesting these pathogens. 2. Which of the following is NOT a characteristic of Gram-positive bacteria? A. Thick peptidoglycan layer B. Outer membrane C. Teichoic acids presence D. Stains purple with Gram staining Answer: B. Outer membrane Rationale: Gram-positive bacteria are characterized by a thick peptidoglycan layer and the presence of teichoic acids. They lack an outer membrane, which is a feature of Gram-negative bacteria. 3. In the context of microbiology, what does the term 'facultative anaerobe' refer to? A. An organism that requires oxygen to survive B. An organism that cannot survive in the presence of oxygen C. An organism that can survive with or without oxygen D. An organism that uses fermentation to produce energy Answer: C. An organism that can survive with or without oxygen Rationale: A facultative anaerobe is an organism that can make ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation or anaerobic respiration if oxygen is absent. 4. Which of the following best describes the function of endospores in bacteria? A. To aid in reproduction B. To facilitate movement