Why are single-stranded binding proteins necessary for dna replication?
a. they direct where replication will start. none of the answer options is correct.
b. they provide the energy necessary to separate the two strands of dna.
c. they direct the primase where to lay down the primer.
d. they prevent the two parental strands from coming together again.

d.They prevent the two parental strands from coming together again.

Explanation:

During the process of DNA replication, the two DNA strands should be separated from each other to serve as a template. To separate the two DNA strands, the helicase enzyme breaks down the hydrogen bonds between the complementary base pairs of the DNA strands. The process uses ATP as a source of energy.

Due to the presence of complementary base pairs, the separated DNA strands have a tendency to reanneal by the formation of hydrogen bonds. To prevent the reannealing of separated DNA strands, single stranded binding proteins bind to them. Binding to single stranded binding proteins to the separated DNA strands does not allow them to reanneal.  

the organisms are not adapted to live in some communities or habitats.