<span>A pathogen exists in the ground air and living thing but does not need them to live or reproduce. It can be a virus, protozoa, parasite, fungus, or bacterium which can cause infection to human. Some pathogens lead to the disease called malaria which is from a bacteria that released toxins in the body. However, our white blood cells can destroy these pathogens.</span>
Atoms combine with other atoms to form compound
