Nitrogen-fixing bacteria

a. repair nitrogen-damaged legume roots
b. convert atmospheric nitrogen into ammonia
c. damage the environment by using atmospheric oxygen to produce toxic nitrogen compounds
d. convert ammonia in the soil into nitrogen gas

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.

preservation because he preserves part of the land and preserves means save

explanation: