Which blood cells have a lifespan of normally about 10 days?

Platelets, also known as thrombocytes, typically have a lifespan of about 7 to 10 days in circulation. They are crucial for hemostasis, helping to form blood clots and prevent excessive bleeding when vessels are injured. Unlike erythrocytes, which can live for approximately 120 days, or leukocytes, which can live from days to years depending on their type, platelets have a much shorter functional lifespan. Monocytes, on the other hand, can live for several days in the bloodstream but can differentiate into macrophages or dendritic cells and live longer once they enter tissues. Therefore, the unique characteristic of platelets having a relatively short lifespan is what makes them the correct answer in this question.