A microorganism that thrives under high hydrostatic pressure is called a(n):

• A. halophile
• B. piezophile
• C. acidophile
• D. thermophile

Answer: (B)

Verified step by step guidance

1. Understand the term 'hydrostatic pressure' which refers to the pressure exerted by a fluid at equilibrium due to the force of gravity. In microbiology, some microorganisms are adapted to live in environments with very high hydrostatic pressure, such as deep ocean trenches.
2. Review the definitions of the given options: 'halophile' refers to organisms that thrive in high salt concentrations; 'acidophile' refers to organisms that thrive in acidic environments; 'thermophile' refers to organisms that thrive at high temperatures.
3. Recognize that the prefix 'piezo-' relates to pressure. Therefore, a 'piezophile' is an organism that prefers or thrives under high pressure conditions.
4. Match the term 'piezophile' with the description of a microorganism that thrives under high hydrostatic pressure, distinguishing it from the other options based on environmental preference.
5. Conclude that the correct term for a microorganism thriving under high hydrostatic pressure is 'piezophile'.