T and B cells. Lymphocytes originate from stem cells in the bone marrow; these stem cells divide continuously, releasing immature lymphocytes into the bloodstream. Some of these cells travel to the thymus, where they multiply and differentiate into T lymphocytes, or T cells.
Cellophane is a thin, transparent sheet made of regenerated cellulose. Its low permeability to air, oils, greases, bacteria and water makes it useful for food packaging. Cellophane is in many countries a registered trade mark of Innovia Films Ltd based in Wigton, Cumbria, United Kingdom.
The main frame of the cello is made from wood. Cellos are normally constructed with a spruce top. The back, sides, and neck are usually made of maple. Other wood are sometimes used for the back and/or sides, usually poplar or pine. The top and back are traditionally hand carved.