What does the prefix 'micro' indicate?

The prefix 'micro' signifies something that is small in size. It is derived from the Greek word 'mikros,' which means tiny or minute. In medical terminology, this prefix is commonly used to describe organisms, structures, or quantities that are exceedingly small, such as microorganisms (tiny living entities like bacteria and viruses), micrograms (a unit of mass equal to one-millionth of a gram), or microscopic examination (looking at samples with a microscope to detect small-scale features).

The other prefixes have distinct meanings: the prefix typically associated with 'good' might be 'eu,' used in terms like 'euphoria' (a state of happiness). The prefix for 'under' is often 'hypo,' as seen in 'hypotension' (low blood pressure). The prefix for 'within' is generally 'intra,' as used in 'intravenous' (within a vein). Therefore, 'micro' clearly indicates size, specifically a smaller scale, making it the correct choice in this context.