Which of the following is an example of susceptibility in plants?

The degree to which a plant is harmed by herbicides exemplifies susceptibility. This concept refers to how vulnerable a plant is to damage or adverse effects from external agents, such as chemicals used in pest control. In this case, susceptibility indicates the plant’s sensitivity to herbicides, which can lead to reduced health or death when exposed.

The other choices mention various plant characteristics but do not directly relate to how a plant responds negatively to a harmful external factor. The ability of a plant to thrive in poor soil encompasses resilience rather than susceptibility. The ease with which a plant can reproduce and the rate of growth compared to other species relate more to growth and reproduction capabilities, not to their response to harmful stimuli. Thus, the focus on how plants react to herbicides clearly illustrates the concept of susceptibility in this context.