All known what animal fossils had no shells or hard preservable parts

In order to form fossils, organisms must have hard parts. These hard parts do not decay easily. These hard parts are quickly buried under the loose sediments like clay and silt, getting separated from the oxygenated environment and after millions of years under the required necessary conditions, it forms fossils. Examples of fossils that have hard parts are brachiopods, gastropods, and cephalopods.

Those organisms that lack these hard parts do not form fossils. Even if they form they are very rare. Some of the organisms that do not have the hard parts are corals, squids (Cephalopods), jellyfish and octopus.

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

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where is the diagram?

if you insert the diagram ill be able to you