1. **State the problem:** Find the prime factors of 13. 2. **Recall the definition:** A prime number is a number greater than 1 that has no positive divisors other than 1 and itself. 3. **List factors of 13:** The factors of 13 are 1 and 13. 4. **Check which factors are prime:** 1 is not prime, 13 is prime. 5. **Conclusion:** The prime factors of 13 are $13$. This completes the solution for the first question (1a).