Question

which best describes a gene?
the short arm of a chromosome
tightly coiled strands of dna
the center of a chromosome
a segment of chromosomal dna

Explanation:

A gene is defined as a segment of DNA that contains the instructions for making a functional product, usually a protein or RNA. The short arm of a chromosome (first option) is a part of the chromosome structure, not a gene. Tightly coiled strands of DNA (second option) refer to the chromatin or chromosome structure, not a gene. The center of a chromosome (third option) is the centromere, a structural part of the chromosome. The fourth option, "a segment of chromosomal DNA", matches the definition of a gene as a specific DNA segment with genetic information.

Answer:

a segment of chromosomal DNA