Question

Which of the following is the most likely way for bacteria and viruses to enter a water supply?

Increased photosynthesis releases bacteria and viruses

Poor sanitation habits cause water to mix with sewage

Water from a burst dam sweeps particulate matter into a nearby river

Chemical fertilizers dumped into the water attract bacteria and viruses

Answer 1

Most likely poor sanitation.
-Bacteria and viruses do not have chloroplats so they cannot perform photosynthesis (some bacteria are exeptions but it's still not a way to enter a water supply)
-Water from a burst dam would probably go through a water treatment plant where the bacteria and viruses are mostly killed.
-Chemical fertilizers dumped in water... the water would probably go through a water treatment plant too.