Final answer:
T cells develop and mature in the thymus gland. As part of the adaptive immune response, T cells undergo a critical maturation process in the thymus to differentiate self from non-self, after which they join the immune system's search for pathogens. The correct option is d.
Step-by-step explanation:
The correct answer to the question "T cells develop and mature within the is Thymus gland. This is because the primary lymphoid organs, which are critical for the maturation of lymphocytes, include both the bone marrow and the thymus gland.
While B cells develop and mature in the bone marrow, T cells leave the bone marrow as progenitors and travel to the thymus, where they complete their development into mature T cells.
T cells are essential to the adaptive immune response, and their maturation process in the thymus involves learning to distinguish between body's own cells and foreign pathogens. After maturing in the thymus, they circulate through the bloodstream and lymphatic system to carry out immune responses. The correct option is d.