Indicate true (T) and false (F) statements below regarding blood leukocytes. Your answer would be a four-letter string composed of letters T and F only, e.g. TTTT.
( ) Most white blood cells use blood merely as a transportation medium, and function in other tissues.
( ) Some granulocytes are professional phagocytes.
( ) Monocytes typically give rise to macrophages and polymorphonuclear leukocytes.
( ) Natural killer cells have a lymphoid origin.