A characteristic of an organism that is determined by protein structure & function (for example hitchhiker's thumb) is called a what?

• A. Gene
• B. Codon
• C. Trait
• D. Genetic code

Answer: (C)

A trait is an observable characteristic of an organism, like hitchhiker's thumb, that comes from how proteins are built and function in the body. The proteins determine the structure and behavior of tissues, so differences in protein production or arrangement lead to different visible features—the trait you can see.

A gene is a specific DNA segment that carries the instructions to make a protein. A codon is a three-nucleotide sequence in mRNA that codes for one amino acid, and the genetic code is the set of rules that maps those codons to amino acids. These ideas describe the genetic system behind the trait, but the trait itself is the observable result.