Task: Question Answering
Input (English): Question: In relation to the bacterial growth in liquid medium not renewed, which of the following statements is correct? 
 Options:  <1> The generation time is a constant parameter. <2> The phase of exponential growth is perpetual. <3> There is a direct relationship between the specific growth rate and the generation time. <4> There is an inverse relationship between the specific growth rate and the generation time. <5> The generation time and the specific growth rate are not related.
Output (English): 4