The poly(A) sequence that is added to RNA during processing: helps prevent rapid breakdown of the messenger RNA. is needed for ribosomes to attach to messenger RNA. aids in the accuracy of translation of the messenger RNA into protein. helps prevent formation of complex three-dimensional structures in the messenger RNA.

Option A, helps prevent rapid breakdown of the messenger RNA

Explanation:

The poly-A tail is a chain of adenine nucleotides which when get attached to the messenger RNA during RNA processing enhances the stability of the molecule and therefore prevents it from breaking down. This is required because after the transcription of gene in a eukaryotic cell, newly formed RNA molecule undergoes several modifications. It also helps is preventing the new RNA from enzymatic degradation in the cytoplasm and translation.

Hence, option A is correct

you are certainly talking about this picture:

a: is the label of the white square, it is showing the  replication fork, formed by helicase (d) ==> so it is the site of dna separation and replication 

b: is a new dna brand that is following directly the replication fork, so it is continuous ==> built continuously from 5' to 3

c: dna polymerase cannot replicate dna on its own, it needs the of their proteins, and one of them plays the role of a clamp which fixes  the dna with the dna template and increases  the processivity of the enzyme. ==>   stops polymerase from falling off the  template.

d: is the enzyme responsible for forming the replication fork (helicase) ==> unwinds and separates dna into two strands

e: is the delayed strand, it is built  in the opposite sense of the helicase, so dna will be built in fragments ==> built  fragments from 5' to 3 joins

and finally f: is the enzyme that builds  the new dna strand (dna polymerase) ==>   adds nucleotides to make a new dna helix.

credit: gradman555p98x9p

read more on -