Which of the following could be a source of biological hazards?

Biological hazards can originate from various sources, each presenting different risks to health and safety. Water can contain harmful microorganisms, such as bacteria and viruses, that can lead to waterborne illnesses. Soil can harbor pathogens, which can be a risk for individuals who come into contact with it, especially in agricultural or landscaping settings. Pathogens themselves, which include bacteria, viruses, fungi, and parasites, are a direct source of biological hazards, capable of causing infections and diseases. Since all three options contribute to the potential presence of biological hazards, the most comprehensive answer identifies the combined threat posed by water, soil, and pathogens, thus confirming that all of these sources are indeed valid.