CBSE Class 9 Answered

DNA is a macromolecule. It is a nucleic acid, a long polymer of simple units called nucleotides, with a backbone made of sugars and phosphate groups joined by ester bonds.

Chromosome is a threadlike linear strand of DNA and associated proteins in the nucleus of eukaryotic cells that carries the genes and functions in the transmission of hereditary information.

Gene is a hereditary unit consisting of a sequence of DNA that occupies a specific location on a chromosome and determines a particular characteristic in an organism.

Chromatin is the organization and dense packaging of DNA in the nucleus of cells.