While the tadpoles of competing species may complete metamorphosis in as little as just a few short months, Bullfrog tadpoles can remain in the same state for as long as one to two years before they actually become adult frogs.
Two types of white blood cells called lymphocytes are vital to the specific immune response. Lymphocytes are produced in the bone marrow, and mature into one of several subtypes. The two most common are T cells and B cells. An antigen is a foreign material that triggers a response from T and B cells.
In adaptive immunity, the bodyâs immune system also forms memory T cells and memory B Cells after the initial exposure, making the immune response much faster and specific on subsequent exposures. 1  B lymphocytes: Humoral immunity pathway by producing immunoglobulin derived from and maturing in bone marrow.