Why are fossil fuels considered nonrenewable resources? A. They take millions of years to form.
B. They cannot be used to create electricity.
C. They form quickly due to decaying biomass.
D. They require both sunlight and water to form.

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.