Step-by-step explanation:
Nucleic acids are specialized in the storage, transmission, and use of information. One of the two types of nucleic acids is DNA (deoxyribonucleic acid) which encodes hereditary information and transmits it from generation to generation. The chemical composition of nucleic acids is nucleotides. The chemical composition of the nucleotides is a Pentose, a phosphate group, and a nitrogenous (pyrimidine or purine). Nucleotides are linked by phosphodiester bonds between the sugar of one nucleotide and the phosphate of the next. DNA helices are held together by hydrogen bonds.
The background of the work of the four scientists was formed by various scientific advances. Among these advances is the progress made by X-ray crystallographers in the study of organic macromolecules. Therefore, before these scientists, there was already knowledge of macromolecules and their composition. In particular, the composition of DNA. What was not very clear was the three-dimensional structure of DNA. In fact, the mounting evidence provided by geneticists that it was the DNA, and not the protein, in the chromosomes that was responsible for heredity; Erwin Chargaff's experimental finding that there are equal numbers of A and T bases and G and C bases in DNA; and Linus Pauling's discovery that some protein molecules have helical shapes, through the use of atomic models and a deep understanding of the possible arrangement of various atoms.
According to this information, we can conclude that the correct answers are:
Answer:
The scientists knew that nucleotides contained nitrogen-containing bases.
The scientists knew that DNA was composed of nucleotides.
The scientists knew that there were four nucleotides: adenine, guanine, cytosine, and thymine.