The tendency of minerals to break along smooth, flat surfaces is called streak fracture cleavage luster

The correct answer is: cleavage.

Cleavage is one of the types of mineral breakage. It is the tendency of a to break along smooth planes which are parallel to zones of weak bonding. Cleavage can be cubic when the break occur in three directions at right angles or it can be rhombohedral when the break occurs in three directions that are not at right angles. There is also one and two-direction cleavage.  

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 real answer is b. scintillation counter