Answer;
A specific sentence.
If a chromosome is like a book, then a gene is like a specific sentence.
Step-by-step explanation;
A chromosome is a structure that is made of a chemical known as deoxyribonucleic acid, or DNA as well as protein. Chromosomes are found in the nucleus of cells. Chromosomes contain many genes. A gene is a molecular unit of heredity, it is a segment of DNA that provides the code to construct a protein.
Chromosomes are made from DNA. Genes are short sections of DNA. Genetically identical cells are produced by a type of cell division called mitosis