What is the proper way to use a fire extinguisher? a. aim at the top of the flames. do not move. b aim at the top of the flames. sweep in circles. c aim at the base of the flames. sweep side to side. d aim at the base of the flames. sweep up and down.

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.

explanation:

b,bacteria convert nitrates

into nitrogen gas.

d,plants and animals take in

and use nitrogen compounds.

e,bacteria break down waste    

products and return nitrogen  

to the soil.

a,bacteria convert atmospheric

nitrogen to ammonia.

c,bacteria convert ammonia

to nitrites and nitrates.