Function. Mechanical contractors are the professionals responsible for the installation of plumbing, heating, cooling, air-conditioning, refrigeration and ventilation systems.efore beginning a job, a mechanical contractor estimates in writing how long it will take to complete a particular job and how much it will cost, and then must complete all required work according to that schedule and in that price range.
In mammals, B cells mature in the bone marrow, which is at the core of most bones. In birds, B cells mature in the bursa of Fabricius, a lymphoid organ. (The B from B cells comes from the name of this organ, where it was first discovered by Chang and Glick, and not from bone marrow as commonly believed). B cells, unlike the other two classes of lymphocytes, T cells and natural killer cells, express B cell receptors (BCRs) on their cell membrane.
Select the correct statement about lymphocytes. A) B cells produce plasma cells, which secrete antibodies into the blood. B) The two main types are T cells and macrophages. C) T cells are the precursors of B cells. D) T cells are the only form of lymphocyte found in lymphoid tissue.A) B cells produce plasma cells, which secrete antibodies into the blood.(this multiple choice question has been scrambled). Select the correct statement about lymphoid tissue. A) Lymphoid tissue is predominantly reticular connective tissue.) T cells are the precursors of B cells. D) T cells are the only form of lymphocyte found in lymphoid tissue. A) B cells produce plasma cells, which secrete antibodies into the blood. (this multiple choice question has been scrambled). Select the correct statement about lymphoid tissue.