It was found by Avery and his team that there is a transforming factor in living organisms which passes on the genetic information from one generation to other and this transforming factor is no other than the DNA. DNA has chromosomes which carries the genetic material responsible for expression of any trait.
Before findings of Avery, it was believed that genetic material was carried through proteins.
You can identify the liquid by finding the density which is 117/15= 7.8, and since density is unique to its substance, use a density chart and find what liquid has a density of 7.8