Answer: 5 or 5, 5
Step-by-step explanation: Prime numbers are numbers that have only 2 factors: 1 and themselves. A factor of a number is a number or quantity that when multiplied with another produces a given number or expression. The only factors of 25 are 1, 5, and 25, and the only number from this list that is prime is 5, so 5 is the only prime factor. 5 is also multiplied by itself to get 25 so the list could also be 5, 5.