## **Core Concept**
The human genome is composed of both coding and non-coding DNA. Coding DNA, also known as exons, contains the sequences that are translated into proteins, while non-coding DNA, including introns, regulatory sequences, and repetitive sequences, does not encode proteins but has other functions.

## **Why the Correct Answer is Right**
The correct answer, only about 2-3% of the human genome encodes for proteins. This small percentage of the genome is responsible for specifying the sequences of amino acids that make up proteins. The rest of the genome is involved in regulatory functions, structural roles, and the origins of replication, among others.

## **Why Each Wrong Option is Incorrect**
* **Option A:** This option suggests a much higher percentage of coding DNA than is accurate.
* **Option B:** This option also overestimates the percentage of coding DNA in the genome.
* **Option D:** This option underestimates the percentage of coding DNA.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that while only a small percentage of the genome codes for proteins, non-coding regions play critical roles in gene regulation and expression. Mutations in non-coding regions can lead to diseases, highlighting their importance.

## **Correct Answer:** . 2-3%