(Need help ASAP) In a research experiment, the population of a colony of bacteria doubles every hour. The population, f(x), of the colony after x hours can be modeled by the function f(x)=25 ⋅ 2x. What values for the domain are reasonable in the given context?
1. all real numbers
2. all real numbers greater than 0
3. all real numbers greater than or equal to 0
4. all real numbers greater than or equal to 25