What classification of toxic substances primarily attacks the species, rather than the individual?

The correct answer, which is mutagen, refers to substances that can cause changes or mutations in the genetic material of organisms. These mutations can be passed on to future generations, thus having an impact on the species as a whole rather than just the individual exposed. Mutagens can lead to long-term genetic changes in populations, affecting their evolution and overall health.

Neurotoxins, while harmful, primarily affect the nervous systems of individuals without necessarily altering genetic material or impacting the species as a whole. Carcinogens cause cancer in individuals due to exposure, but their effects are also more immediate and specific to those exposed rather than broad-spectrum effects on a species. Teratogens can cause developmental malformations in embryos or fetuses primarily within individuals, impacting reproductive success but not inducing genetic changes that affect the species collectively.