Which best describes a gene?

• A. A segment of RNA that allows for protein synthesis
• B. A piece of DNA coding for a specific characteristic
• C. A component of the endocrine system
• D. A type of neurotransmitter

Answer: (B)

A gene is indeed best described as a piece of DNA coding for a specific characteristic. Genes are sequences of nucleotides found within the DNA that provide the instructions for synthesizing proteins, which play crucial roles in determining an organism's traits, including physical appearance, biochemical properties, and overall function. Each gene contains the information necessary for producing particular proteins that influence various characteristics, making them fundamental units of heredity.

To clarify the context of the other options: A segment of RNA is not a gene itself; rather, RNA is transcribed from DNA and is involved in protein synthesis. The endocrine system refers to a collection of glands that produce hormones, which is unrelated to the definition of a gene. Neurotransmitters are chemicals that transmit signals across synapses between neurons and do not relate directly to the concept of a gene or its function.