Name the anticoagulant present in blood.

Explanation

**Step-by-Step Solution:**

1. **Understanding Anticoagulants**: Anticoagulants are substances that prevent blood from clotting. They play a crucial role in maintaining normal blood flow and preventing unwanted clot formation.

2. **Identifying the Natural Anticoagulant in Blood**: In the human body, there are several substances that can act as anticoagulants. However, the primary natural anticoagulant found in blood is heparin.

3. **Function of Heparin**: Heparin works by inhibiting certain factors in the blood coagulation process, thereby preventing the formation of blood clots. This is particularly important in various physiological and pathological conditions.

...