Which of these is NOT a characteristic of pathogens?

The answer identifies that pathogens are not always beneficial, which aligns with the understanding of what pathogens are. Pathogens are organisms that can cause disease or illness in their hosts. This harmful aspect is a defining characteristic of pathogens, as they are known to create negative impacts on health, such as infections or diseases.

While some microorganisms can play beneficial roles in processes such as digestion or immunity, pathogens specifically are recognized for their potential to cause harm. Thus, stating that they are always beneficial is indeed incorrect.

On the contrary, the other characteristics are true of pathogens. They have the ability to reproduce, which is essential for their survival and propagation. Pathogens can also cause illness through various mechanisms, and they can be classified as either viral or bacterial, representing different categories of infectious agents. Each of these attributes highlights the complex nature of pathogens in the context of health and disease.