Help with this biology multiple choice question?

Herbivory;

Animals that eat plants (herbivores) are less likely to continue doing so if they start dying from said action. Producing nicotine ensures that, although a couple plants may be eaten, the species survives. Plants are real team-players.

Herbivory.
Predation is associated with animals. Competition for space and light sometimes does occur among plants, but these substances would not deter another plant to grow unless they are released by the roots, and even then, the substances would have to make the soil inhabitable for another species to take root (walnut trees do this). I think these substances are contained in the upper parts of the plant, not the roots. (i certainly could be wrong.) Symbiosis would suggest that two species exist together, and that each benefits by something the other species does for it and the two have enhanced survival b/c of it. In this situation, the one species is a plant and the substances they make are organic molecules - not another species. So, herbivory of the plant may result in a bad physiological effect (sickness) in the herbivore, and so they tend to avoid the plant (the plant benefits by being left alone) OR it may create an addiction to the plant and the herbivore may engage in ways that protect, propagate, or preserve the plant.

Otters.

herbivory