Answer:
Exponential growth
Step-by-step explanation:
Exponential growth is a fundamental population estimate mechanism in which the population of an organism grows at a rate which is related to the present population of the organism such as doubling the present population, square of the present population, half of the present population etc.
Here it is given that the bacterial counts becomes double every two hours which means that the population of bacteria is increasing at the rate of 2 times its present population after every two hours .
Hence this is a situation of exponential growth