A stretch of chromosome that codes for a trait can be called a(n):
a) centromere
b) gene
c) lipid
d) tRNA
of DNA is called a:

             b) Gene

Explanation:

                      Gene is the basic unit of inheritance. Each gene control a specific trait in the body the word trait was first time use by Mendel in genetics which he called a factor. Gene is a segment of chromosome that code for a specific mRNA  and then  tRNA and is transcribed to amino acid. Each gene have a sequence of three nitrogenous bases with sugar and phosphate group that make the nucleotide each gene is compose of three nucleotide that code foe a specific amino acid and many amino acid combines to form a peptide and peptides combine to form protein.