Question

1. b and t cells spend most of their time in the

a. heart chambers.
b. bloodstream.
c. capillaries.
d. lymphatic system.

Explanation:

B and T cells are key components of the immune system. The lymphatic system (including lymph nodes, lymph vessels, etc.) is where these immune cells mature, reside, and interact to mount immune responses. Heart chambers (a) are for blood pumping, not immune cell residence. While they circulate in the bloodstream (b) and capillaries (c), they spend most time in the lymphatic system.

Answer:

d. Lymphatic system.