What term refers to the act of examining or investigating thoroughly?

The term that best refers to the act of examining or investigating thoroughly is "scrutiny." Scrutiny involves a careful and detailed examination of something, implying a level of intensity and depth in the investigation. It suggests not just a surface-level look but a deep dive into the elements and details to fully understand or evaluate.

While "inquiry" indicates a process of seeking information or knowledge, and "probe" refers to an act of probing or investigating, neither conveys the same connotation of meticulous examination as "scrutiny." "Survey," on the other hand, typically suggests a broader overview or assessment rather than a thorough examination. Therefore, "scrutiny" is the term that accurately captures the essence of thorough investigation.