Explain why tobacco mosaic virus is considered a widespread pathogen.

Tobacco mosaic virus is considered a widespread pathogen because it infects a variety of plant species, particularly those in the Solanaceae family, such as tomatoes and peppers. Its ability to spread easily through mechanical means and contaminated tools contributes to its prevalence.

This answer is strong as it not only identifies the virus as widespread but also provides reasoning related to its transmission and host range. The question tests the student's ability to explain the concept of widespread pathogens.