Most of the eukaryotic genes have stretches of bases that code for amino acids, which are called

Options

A. Exons
B. Introns
C. Axons
D. Cistrons

Answer

To solve the question regarding the stretches of bases in eukaryotic genes that code for amino acids, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for the term that refers to stretches of bases in eukaryotic genes that code for amino acids.

2. **Identify Key Terms**: The options provided are axons, introns, and cisterons. We need to determine which of these terms correctly describes the coding regions of genes.

3. **Define the Terms**:
- **Axons**: These are the coding sequences in a gene that are expressed and translated into proteins. They contain the information necessary to produce amino acids.
- **Introns**: These are non-coding sequences found within genes. They do not code for amino acids and are removed during RNA processing.
- **Cisterons**: This term is not commonly used in genetics and does not refer to any known genetic component.

4. **Analyze the Options**:
- **Axons**: Correct, as they code for amino acids.
- **Introns**: Incorrect, as they do not code for amino acids.
- **Cisterons**: Incorrect, as this term is not relevant in this context.

5. **Conclusion**: The correct answer is **axons**, as they are the sections of the RNA transcript that code for amino acids.

### Final Answer:
The stretches of bases that code for amino acids in eukaryotic genes are called **axons**.

---