Give the term for percentage of oxygen used by the body tissues.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a specific term that represents the percentage of oxygen utilized by body tissues.

2. **Oxygen in Blood**: In the human body, oxygen is present in two forms:
- About 1.5% of oxygen is dissolved directly in the blood.
- Approximately 98.5% of oxygen is bound to hemoglobin in red blood cells.

...