1. Which of the following is an essential nutrient for bacteria? A) Carbon B) Nitrogen C) Oxygen D) All of the above Answer: D) All of the above Rationale: Bacteria require carbon, nitrogen, and oxygen for various cellular processes such as energy production, growth, and replication. 2. A bacterium living in a hot spring would most likely be classified as a: A) Mesophile B) Thermophile C) Psychrophile D) Acidophile Answer: B) Thermophile Rationale: Thermophiles are organisms that thrive at relatively high temperatures, such as those found in hot springs. 3. Which type of metabolism is primarily used by bacteria to obtain energy from light? A) Chemotrophy B) Phototrophy C) Heterotrophy D) Lithotrophy Answer: B) Phototrophy Rationale: Phototrophy involves the use of light as an energy source, which is utilized by photosynthetic bacteria. 4. In the context of microbial nutrition, what does the term 'auxotroph' refer to? A) A microorganism that can synthesize all its required nutrients B) A microorganism that requires additional nutrients from its environment C) A microorganism that can fix nitrogen D) A microorganism that utilizes inorganic compounds Answer: B) A microorganism that requires additional nutrients from its environment