Chromosomes contain thousands of segments called

A) nuclei.
B) genes.
C) phosphates.
D) cytosines.

Chromosomes

Rod-shaped structures that are composed of genes and found within the nuclei of cells.

Genes

Units of heredity made up of DNA that act as instructions to make molecules called proteins, crucial for the development, functionality, and regulation of the body's tissues and organs.

Cytosines

One of the four main nucleobases found in DNA and RNA, which pairs with guanine during the nucleic acids' synthesis.