Aregion that includes several interacting ecosystems is called

The cells in a population die at a constant rate

Explanation:

Microbial death is the loss of the ability of microbes to reproduce and survive in an environment. When a given microbial population is given a treatment, the microbial cells die at a constant rate. Microbial death rate  is not dependent on the specie and nor on the antimicrobial agent.

Therefore, the microbial cells in a population does not die at once but die at a constant logarithmic rate; the cells decreases exponentially as nutrients decreases and waste product increases.

For example, if 500,000 microbes are treated or in a nutrient depleted environment and 50,000 microbes is left after 1 minute, by the next minute under the same condition 5,000 microbial cells will be left and this pattern will continue, this explains exponential decrease