. What is true about T-lymphocytes in mammals ?
(a) They scavenge damaged cells and cellular debris
(b) These are produced in thyroid
(c) There are of three main types—cytotoxic T-cells, helper T-cells and suppressor T-cells
(d) These originate in lymphoid tissues
Sol.The function of T-cells is to provide immunity (cellular type) and not to scavenge damaged cells and cell debris. These are produced in bone marrow and mature in thyroid. Hence, the only true statement is that there are three types of T-cells-cytotwric, helper and suppressor.