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.
T cells release proteins that help stimulate the B cells, and can also stimulate the death of our bodyâs cells to prevent infection from spreading. B cells are âkillerâ cells that immediately begin to fight infections. T cells can also release chemicals which cause specialized B cells, called phagocytes, to produce responses in the body that make environments inhospitable for infection.