Final answer:
The natural anticoagulant found in basophils is 1) heparin. Heparin is a substance that prevents blood from clotting within the blood vessels, different from warfarin, aspirin, and clopidogrel, which are drug-based anticoagulants.
Step-by-step explanation:
The natural anticoagulant found in basophils is heparin. Basophils are a type of white blood cell, specifically a granulocyte, that are part of the body's immune response and play a role in inflammatory reactions. They contain large granules which store various biochemical substances, including histamine and heparin. Heparin is an important substance that helps to prevent blood from clotting too easily within the blood vessels.
Heparin is quite different from the other substances listed in the options. While warfarin, aspirin, and clopidogrel are also anticoagulants, they are not naturally produced by the body. They are pharmaceutical drugs that people may take to reduce the risk of blood clots. Warfarin works by inhibiting vitamin K-dependent clotting factors, aspirin inhibits platelet aggregation, and clopidogrel blocks an ADP receptor on platelets. Therefore, the correct answer from the options provided is 1) Heparin.