Which of the following is true of a semi-conservative model of replication?
1) Each newly synthesized double helix of DNA contains one new strand and one old strand.
2)DNA synthesis involves conserving only part of each of the original strands in a DNA molecule.
3)The original DNA molecule is stored in the cell nucleus and serves as a template for creating copies containing two new strands.
4)DNA synthesis involves conserving one strand of a double helix of DNA and discarding the other.