Final answer:
The number of cells per milliliter would likely increase if the bacteria are in the exponential growth phase, characterized by rapid cell division. This is observed when bacteria divide by binary fission in a liquid medium with adequate conditions.
Step-by-step explanation:
When considering the growth of bacteria in a liquid growth medium, typically most bacteria, such as E. coli, divide by a process called binary fission, leading to exponential population growth. The generation time, or the time it takes for a bacterial population to double, can vary depending on the species and environmental conditions. When bacteria are grown in a closed system, they usually exhibit a growth curve with four phases: the lag phase, the exponential (logarithmic) phase, the stationary phase, and the death phase. Given ideal conditions, such as adequate nutrients and space, the number of bacteria per milliliter would increase during the exponential phase. To accurately measure this growth, microbiologists may use direct methods like viable cell counts, which could be performed via pour plate or spread plate techniques, or indirect methods, such as turbidity measurements with a spectrophotometer. The growth of bacterial cultures in closed environments can be unpredictable and follows a distinct pattern that includes a period of rapid cell division, making the answer (A) Increased the most likely if the bacteria are in the exponential growth phase, which is characterized by a constant and rapid increase in cell number.