Answer
DNA is composed by pentose sugar+heterocyclic base+Phosphate Phosphilipid is composed by Phosphate + 2 Hydrocarbon chain joined by ester bond (with glycerol) and in some cases the phosphate is modified by chlone or ethanolamine or serine. As some antibody reacts with both DNA and phospholipid where common part in both the cases is the phosphate. Hence the best answer will be Phosphate group.
Work Step by Step
DNA is composed by pentose sugar+heterocyclic base+Phosphate Phosphilipid is composed by Phosphate + 2 Hydrocarbon chain joined by ester bond (with glycerol) and in some cases the phosphate is modified by chlone or ethanolamine or serine. As some antibody reacts with both DNA and phospholipid where common part in both the cases is the phosphate. Hence the best answer will be Phosphate group.