Which statement is true about nonpathogen microbes?

Nonpathogen microbes are typically characterized by their lack of disease-causing properties in healthy individuals. The statement regarding their usual behavior highlights that these microorganisms frequently coexist with humans and other environments without leading to harmful infections or diseases.

Many nonpathogenic microbes play essential roles in various ecosystems, including human bodies, where they can contribute to beneficial functions such as digestion and immune system support. The normal flora of the human body includes many nonpathogens that help in maintaining health and preventing infections from harmful pathogens.

The other statements do not accurately describe nonpathogen microbes. They do not always cause illness; in fact, their primary characteristic is that they typically do not cause infections in healthy individuals. Moreover, they are not inherently harmful, as many contribute positively to their environment or host.