True or false , when dna unwinds, one old strand is used to make one new strand

What is the mrna strand that would be copied from this dna strand

In dna, only the_ varies from one nucleotide to another. base phosphate sugar amino acid

Which ideas did your answer contain? check all that apply. no food for organisms no oxygen in the atmosphere no trees or flowering plants no products based on trees or plants (building materials, medicines, fuels, fibers) no fossil fuels