Which of the following best describes an extremophile in microbiology?

• A. A microorganism that thrives in extreme environmental conditions, such as high temperature, acidity, or salinity.
• B. A microorganism that causes disease in humans.
• C. A microorganism that is used in the production of antibiotics.
• D. A microorganism that can only survive in the presence of oxygen.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the term 'extremophile' by breaking down its components: 'extreme' refers to harsh or unusual environmental conditions, and 'phile' means 'lover of' or 'thrives in'.
2. Step 2: Recognize that extremophiles are microorganisms adapted to survive and grow in conditions that are extreme compared to normal environments, such as very high or low temperatures, high acidity or alkalinity, or high salt concentrations.
3. Step 3: Compare the given options to the definition of extremophiles. Identify which option describes organisms thriving in extreme conditions rather than causing disease, producing antibiotics, or requiring oxygen.
4. Step 4: Eliminate options that describe pathogens (microorganisms causing disease), industrially useful microbes (antibiotic producers), or oxygen-dependent microbes, as these do not specifically relate to extremophiles.
5. Step 5: Conclude that the best description of an extremophile is a microorganism that thrives in extreme environmental conditions, such as high temperature, acidity, or salinity.