During which stage is dna in the nucleus duplicated?

In the practice of science, this type of reasoning is used to develop explanations.

Recombinant dna is the merging of dna from unrelated organisms to create new genetic varieties is assembled in the lab from mononucleotides was part of the green revolution of the 1960s is pollination of one plant by another of the same species is cross-pollination of one plant by a different species

Explain why scientists use the word dominant for certain traits.