Identify the Prime Factor in this ??5 Number

We need to determine which prime factor is guaranteed for the number's appearance. The number is a three-digit number ending with 5, indicated as $??5$.

Based on divisibility rules, a number ending in 5 is divisible by 5. Therefore, 5 must be a factor.

Thus, the prime factor that surely appears in the factorization of any number ending in 5 is $5$.

Therefore, the solution to the problem is $5$.