Justin Bieber was born March 1, 1994 and grew up in Stratford, Ontario, Canada. Justin Bieber is 23 years old. At the age of 12 he entered a local singing competition against others who had significantly more experience and the benefit of vocal coaches. Justin Bieber came in second place singing Ne-Yo's So Sick..
Platelet. An irregularly shaped cell-like particle in the blood that is an important part of blood clotting. Platelets are activated when an injury causes a blood vessel to break. They change shape from round to spiny, sticking to the broken vessel wall and to each other to begin the clotting process.
1 doctor agreed: Blood clotting: There are proteins in our body such as thrombin, prothrombin, fibrin that play an important role in blood clotting, also blood paticles called platelets take part of coaguation.