What is the primary characteristic of histotoxic hypoxia?

The primary characteristic of histotoxic hypoxia is indeed the inability of blood cells to utilize oxygen. This condition occurs when the body's tissues are unable to effectively use the oxygen supplied to them due to the presence of toxic substances, such as carbon monoxide or cyanide. These toxins interfere with the cellular processes that require oxygen, even if adequate amounts of oxygen are available in the bloodstream.

In contrast to this, insufficient oxygen supply refers to a general lack of oxygen available to meet the body's needs, which does not specifically address the cellular utilization aspect. Inadequate blood circulation relates to issues with the flow of blood, impacting the delivery of oxygen but not the utilization at the cellular level. Low oxygen levels in blood are indicative of hypoxia as a general phenomenon but do not pinpoint the unique mechanism involved in histotoxic hypoxia. Therefore, the inability of cells to utilize oxygen, despite its availability, defines the specific nature of histotoxic hypoxia.