Final answer:
Protozoa are the one-cell organisms that love moisture and often spread diseases through water.
Step-by-step explanation:
The one-cell organisms that love moisture and often spread diseases through water are protozoa.
Protozoa are one-celled organisms with a nucleus, making them eukaryotic organisms. They cause diseases such as malaria and diarrhea. For example, Giardia lamblia is a protozoa that causes severe diarrhea when ingested through contaminated water supplies.