During the process of two rails break apart and attract new nucleotide bases to form a new and complete strand

i think chromosome is the word you are looking for..

During the process of, two rails break apart and attract new nucleotide bases to form a new and complete strand

you didn't give any options but heres what i can tell you: an inference is likely to change based on additional observations. the latter is something that you have seen or sensed using your sensory organs while the former is like a conclusion out from what you have observed.