Effector cells
are formed in the red bone marrow.
all of these.
are involved in bringing about the immune response of killing pathogens and infected host cells.
are either B plasma cells or Tc cells.
are lymphocytes.

The image shows the evolution of a species of fish. a few fish from a population developed different social behaviors and evolved into different species. two fish according to the image, the fish underwent . the new species of fish had mating seasons that were different from that of the original fish. because of the differences in mating seasons, the fish underwent reproductive isolation. this mode of isolation would be .