What does hypoxia refer to?

Hypoxia specifically refers to a condition in which there is a deficiency of oxygen in the tissues. This condition can arise from various factors, including insufficient oxygen saturation in the blood. When the oxygen levels decrease, it can impair the body's ability to function properly, leading to potentially serious health issues. Therefore, insufficient oxygen saturation in the blood directly aligns with the definition of hypoxia, making it the correct choice in this context.

The other options focus on unrelated concepts, such as excessive blood supply, which would suggest an abundance rather than a deficiency of oxygen; an area of dead tissue, which is known as necrosis and can result from prolonged hypoxia but is not synonymous with it; and increased liver size, which pertains to hepatomegaly and can stem from various medical conditions but does not relate to the levels of oxygen in the body.