Marita is analyzing the population of various songbirds in her neighborhood. She estimates how the population is increasing by and decreasing by , as different birds enter and leave the area. She thinks that the blue jay population increased by because it doubled over a short time, but then it followed a pattern of when the population approached the .

white blood cells or wbc s are mainly 2 types-

1.agranulocytes

2.granulocytes

the monocytes or macrophages of agranulocytes , dendritic cells which are accessory leucocytes, and b cells which is one type of lymphocytes   identify the antigens present on the pathogen's surface. these three cells are called antigen presenting cells(apc) which are phagocytes and destroy the antigens by secreting antitoxins. besides this leukocyte is always plays vital role in the immunity of the body.