Explain how this enables the bacterium to detect the population density

The concentration of chemical auto inducers increases with increase in population density

Explanation:

There is something known as Quorum sensing which is a sort of cellular communication in bacteria established through chemical signals. A bacterium is enabled to observe/monitor the environment and thus produce a widespread change in the species with in a community. These sensing processes are effective only when large numbers of cells are doing sensing controlled process together. A bacteria releases auto-inducers whose concentration increases when the population density of cells increase.

i think its through the fallopian tube