Final answer:
A potential source of disease from outside our body can be pathogenic organisms such as bacteria, viruses, protozoa, and parasites. These infectious agents can enter our body through various portals of entry, and can also spread through contaminated surfaces and objects.
Step-by-step explanation:
A potential source of disease from outside our body can be pathogenic organisms such as bacteria, viruses, protozoa, and parasites. These infectious agents can enter our body through various portals of entry, such as the skin, mucous membranes, and parenteral routes. Furthermore, pathogens can also spread through contaminated surfaces and objects.
For example, you can get athlete's foot fungus by wearing shoes that have been worn by an infected person or by walking barefoot in public showers. Additionally, pathogenic bacteria can cause diseases like tetanus, syphilis, and food poisoning.
It's important to note that industrial pollution and the dumping of toxic waste into the environment can also contribute to the degradation of ecosystems, which ultimately affects human health and well-being.