Final answer:
The bone marrow of a healthy adult animal contains hematopoietic stem cells, which differentiate into various blood cells including phagocytic cells and lymphocytes, with the latter mainly comprised of T cells and B cells.
Step-by-step explanation:
The question pertains to the composition of cells in the bone marrow of a healthy adult animal. The bone marrow has a wide variety of cells, which include hematopoietic stem cells that differentiate into various types of blood cells. There are different types of blood cells with varying functions such as phagocytic cells, which destroy pathogens, and lymphocytes, which are crucial for adaptive immunity. These can be further categorized as T cells and B cells, with T cells being involved in cell-mediated immunity and B cells in humoral immune responses. In terms of percentages, it is noted that lymphocytes in human circulating blood are approximately 80 to 90 percent T cells and 10 to 20 percent B cells.
The bone marrow is responsible for the hematopoiesis process, which takes place in the red bone marrow, and is contrasted by the yellow bone marrow, which is primarily for energy storage. Furthermore, blood constitutes approximately 8 percent of an adult's body weight, with males averaging about 5 to 6 liters and females 4-5 liters of blood.