The correct order of organization of genetic material from largest to smallest is:

Genome > Chromosome > Gene > Nucleotide

Genome: It is the complete set of genetic material or DNA present in a cell or an organism, including all the genes, regulatory sequences, and non-coding DNA.

Chromosome: It is a thread-like structure made up of DNA and protein that carries genetic information in the form of genes. In eukaryotic cells, chromosomes are found in the nucleus, while in prokaryotic cells, they are present in the cytoplasm.

Gene: It is a unit of heredity that carries information for the synthesis of a particular protein or RNA molecule. A gene is a sequence of DNA that is transcribed into RNA and then translated into a protein.

Nucleotide: It is the basic building block of DNA and RNA, consisting of a nitrogenous base, a sugar molecule, and a phosphate group. The sequence of nucleotides in DNA determines the genetic information and the traits of an organism.

Therefore, the correct order of organization of genetic material from largest to smallest is genome > chromosome > gene > nucleotide, where genome is the largest and nucleotide is the smallest unit.