Final answer:
A gene is a segment of DNA that carries a code for making a specific polypeptide chain. Genes specify the sequences of amino acids, which are the building blocks of proteins.
Step-by-step explanation:
A gene is a segment of DNA that carries a code for making a specific polypeptide chain. Genes are composed of DNA and are linearly arranged on chromosomes.
They specify the sequences of amino acids, which are the building blocks of proteins. Both genes and the proteins they encode are essential to life.