Ground squirrels are found in many areas of the United States. They live in underground burrows and are often attacked by birds of prey, coyotes, and bobcats. Which of the following is a limiting factor for a ground squirrel population? a population of tree squirrels
a population of hawks
genetic variability
breeding season

this protocol provides a detailed procedure for nucleoprotein extraction from cultured cells and tissues in an efficient manner.

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.