Where is blood produced?

Well at a glance, this looks like a very simple question a primary school student would ask their teachers, and a quick intelligent response to that question would be in the bone marrow. Technically, that is a correct answer. However, blood has not been entirely produced in the bone marrow through out our entire lives. In fact, blood started to be produced in the bone marrows after 6 months of life. So, let's search a little bit further to understand where blood is actually produced.

Hematopoiesis or hemopoiesis is the "expensive medical term" that medical students (and the medical community) use to say the production of blood cells. As stated earlier, bone marrow was not the production site for blood our entire lives.
Our blood factories have changed places as we grow older and can be seen in this table.