When a blood clot is formed inside a blood vessel, this condition is called ……………….. .

Explanation

**Step-by-Step Solution:**

1. **Understanding Blood Vessels**: Blood vessels are tubes through which blood circulates in the body. They include arteries, veins, and capillaries.

2. **Formation of Blood Clots**: A blood clot forms when blood cells and proteins stick together in a solid mass. This can happen in response to injury or certain medical conditions.

3. **Identifying the Condition**: When a blood clot forms inside a blood vessel, it can obstruct the flow of blood. This condition is specifically referred to as "thrombosis."

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