During a humoral immune response, which of the following happens when a pathogen is recognized? multiple choice between: memory b cells divide to form plasma cells that surround the pathogen. the antibodies on b cells bind to the antigens on the pathogen's surface. memory t cells produce t cells that search for the pathogen and destroy it. t cells signal cytotoxic t cells to attack cells infected by the pathogen.

regulation of gene expression. gene expression can be regulated by various cellular processes with the aim to control the amount and nature of the expressed genes. these regulatory proteins bind to dna and send signals that indirectly control the rate of gene expression

explanation:

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.