The secretory structures that produce milk in a lactating female are the:

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.

several tissues working together form an organ, and several organs together make up an organisms.

the group of cell that carries out special jobs are tissue.