What is known as the genetic material of living cellular organisms?

The genetic material of living cellular organisms is DNA, which stands for deoxyribonucleic acid. This double-helix structure carries the genetic instructions necessary for the growth, development, functioning, and reproduction of all known living organisms and many viruses. DNA contains specific sequences of nucleotides that encode the information needed to produce proteins, which in turn carry out various functions within the cell.

In contrast, RNA (ribonucleic acid) plays a critical role in translating the information encoded in DNA into proteins but is not the genetic material itself. Chromatin refers to the complex of DNA and proteins found in the nucleus of eukaryotic cells, which aids in the packaging of DNA, but is not the genetic material. Proteins, while essential for many cellular functions and processes, are synthesized based on the information provided by DNA and therefore cannot serve as the genetic material themselves. Thus, among the listed options, DNA is unequivocally recognized as the fundamental molecule that stores and transmits genetic information in living organisms.