Final answer:
The question is about the most technically difficult and time-consuming system to examine completely, and my answer explains that it is most likely referring to the nervous system due to its complexity.
Step-by-step explanation:
The subject of this question is Biology. The question discusses the difficulty and time-consuming nature of examining a particular system, which is usually reserved for patients with known or suspected diseases of that system. In the given references, the nervous system and the cardiovascular system are mentioned, but the specific system being referred to is not explicitly mentioned. However, considering the difficulty and complexity mentioned in the question, it is most likely referring to the nervous system. The nervous system is indeed a complex organ system, and a complete examination of this system is challenging due to its intricacy.