I nclude the bone marrow, lymph nodes, spleen, and thymus. Precursor cells in the bone marrow produce lymphocytes. B-lymphocytes (B-cells) mature in the bone marrow. T-lymphocytes (T-cells) mature in the thymus gland. Besides providing a home for lymphocytes (B-cells and T-cells), the ducts of the lymphatic system provide transportation for proteins, fats, and other substances in a medium called lymph.
A book that is made with a stiff paper cover and bound directly to the text block. Many paperback books are converted to hardcover books by mylar binding. Perfect bind
block. 1  a solid mass of wood, stone, etc., usually with one or more flat or approximately flat faces. 2  a hollow masonry building unit of cement, terra cotta, etc.: a wall made of concrete blocks. 3  one of a set of cube-shaped pieces of wood, plastic, or the like, used as a child's toy in building. a mold or piece on which something is shaped or kept in shape: a hat block. a piece of wood used in the art of making woodcuts or wood engravings. Printing. the base on which a plate is mounted to make it type-high.