Platelets are a source of:

• A. Clotting factors
• B. Hemoglobin
• C. Triglycerides
• D. Antibodies

Answer: (A)

Platelets support clot formation by providing a surface for coagulation reactions and by releasing granule contents that help drive the clotting process. In their alpha granules they store clotting-related proteins such as fibrinogen and factor V, which participate in forming a stable clot when platelets are activated. This makes platelets a source of clotting factors. Hemoglobin is in red blood cells, triglycerides are lipids carried in plasma, and antibodies are produced by B cells and circulate in serum, not coming from platelets.