Which of the following is most critical for the association between histones and dna?

histones are small proteins.
histones are highly conserved (i. e., histones are very similar in every eukaryote).
there are at least five different histone proteins in every eukaryote.
histones are synthesized in the cytoplasm.
histones are positively charged.

The correct answer is - Histones are positively charged.

Explanation:

Histone is an octamer that is made up of four proteins and each protein has 2 copies. These proteins are H2A, H2B, H3, and H4. Histone proteins are mainly made up of positively charged amino acids like arginine and lysine which gives histone proteins an overall positive charge.

This positive charge of histone plays important role in the binding of DNA around it because phosphate group present in the DNA makes DNA negatively charged molecules that are attracted by positively charged histone protein by electrostatic interaction.

This interaction results in the wrapping of DNA around the histone proteins and then compaction of DNA into chromatin. Therefore the right answer is- histones are positively charged.

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.