11. what are the steps involved in dna replication? a. replication begins when the dna double helix b. the nitrogenous base pairs pull apart from each other at a exposing the two strands. c. as the double helix continues to open, new nitrogenous are added on both sides.

DNA replication is the process in which a new DNA strand is synthesised from the existing DNA strand using that as the template.
DNA strands are built from building blocks of units called nucleotides, DNA exists as a double helix which means that two complementary strands are wound around each other and bonded by hydrogen bonds between the nitrogenous bases in the nucleotides.
1. replication begins when the DNA double helix unwinds
DNA helicase breaks the Hydrogen bonds keeping the two strands together and unwinds the helix so that the two strands are exposed for replication to be initiated.

2 . the nitrogenous bases pull apart from each other at a distance, exposing the two strands
The two strands pull apart from each other so that the strands are exposed for them to be used as templates in synthesising the new strands 

3. as the double helix continues to open, new nitrogenous bases are added on both sides
nucleotides consist of nitrogenous bases, phosphate group and pentose sugar. the uniqueness of DNA strands are in the sequence of nucleotides. the bases added to the new strand are complementary bases to that already in the template strand

Ithink the answer is d.