Question

which phrase correctly defines a gene?
a segment of dna
a segment of fatty acid chain
a segment of a protein
a segment of rna

Explanation:

A gene is a fundamental unit of heredity. It is composed of DNA. DNA (deoxyribonucleic acid) contains the genetic instructions for the development, functioning, growth, and reproduction of all known living organisms. RNA (ribonucleic acid) is often involved in processes related to gene expression (such as mRNA carrying the genetic code from DNA to the ribosome for protein synthesis), but a gene itself is a segment of DNA. Proteins are the products of gene expression (after transcription and translation processes). Fatty acid chains are part of lipids and have no direct relation to the definition of a gene.

Answer:

a segment of DNA