What is the main characteristic of hypoxia?

The main characteristic of hypoxia is insufficient cellular tissue oxygenation. This condition occurs when there is an inadequate supply of oxygen to the tissues, which can hinder cellular metabolism and energy production. Cells rely on oxygen to perform vital functions, and when these levels drop, cells may become dysfunctional, leading to various health complications.

In contrast, excessive oxygenation of tissues implies that there is an abundance of oxygen available, which does not characterize hypoxia. Similarly, low carbon dioxide levels in the blood do not directly indicate the state of tissue oxygenation; instead, they may stem from other respiratory conditions. Increased oxygen saturation in the blood suggests that the blood is carrying a higher level of oxygen than normal, which would not support the definition of hypoxia. The essence of hypoxia is fundamentally tied to the insufficiency of oxygen at the cellular level, making insufficient cellular tissue oxygenation the correct answer.