In the early days of germ theory, contagious diseases were thought to be caused only by fungi or bacteria. In the
1890s,
Dmitri Ivanovski filtered extracts from diseased tobacco plants and discovered that the disease could be transmitted to
new plants through the filtrate. He hypothesized that something smaller than bacteria or fungi was responsible for the
transmission of the disease.

Which best explains how lvanovski's work led to a change in the germ theory?
He tried to promote his hypothesis as a law.
O He used a new experimental method to test his hypothesis.
O He used a more powerful bacterial strain than other scientists had.
O He obtained results that confirmed what other scientists were thinking.

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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the question isn't complete here so i can't right an answer '_'

well the answer is 2!