Question

Based on the way natural selection works, what is the BEST way to make use of antibacterial soap?

a) Always use it because most bacteria will cause illness.
b) Use it most of the time as it is unlikely that bacteria will evolve to become resistant to it.
c) Never use it because bacteria will evolve to become resistant to it.
d) Use it only when you need to be free of bacterial contamination, but not a lot, so bacteria will not evolve resistance to it.
e) Never use it because all bacteria are harmless.

Answer 1

d) Use it only when you need to be free of bacterial contamination, but not a lot, so bacteria will not evolve resistance to it.

Anti Bacterial soap doesn't kill off all bacteria, rather just some. The bacteria that aren't killed by it will continue to reproduce and by natural selection, will become resistant to the antibacterial soap. By only using it when absolutely necessary, the rate of natural adaptation and selection is reduced, making to the antibacterial soap will be more effective for longer.