What are chromosomes? Building blocks?

The library. The chromosomes are the library of instructions that tell each cell of the body what to do and how to do it.Each chromosome has subunits of code, that provide instructions on metabolic activities, how tissues should form, what goes where. They tell the cells how to use nutrients to create energy, proteins and build the tissues.
See below: Chro·mo·some; 1. 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. 2. A circular strand of dna in bacteria that contains the hereditary information necessary for cell life.