A species' realized niche . cannot be larger than its fundamental niche cannot be smaller than its fundamental niche is the niche that a species realizes/experiences in the absence of competition is never really realized because it isn't real is the portion of a species' niche that is "taken over" by competing species

C. cannot be larger than its fundamental niche

it would be c. xylem.

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.