Blood coagulation is the process by which liquid blood changes into semisolid
blood clots. It helps preventing blood loss from damaged blood vessels.
Source: GreenFacts
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When a blood vessel is damaged, small blood particles called platelets
immediately form a plug at the site of injury. Shortly after, blood proteins,
called coagulation factors or clotting factors, respond in a complex cascade to
strengthen the platelet plug. Later, the wound heals and the platelet plug is
broken down.