Which characteristic damage is indicative of plant issues?

The correct choice highlights that unusual growth habits and unique flowers can indicate plant issues. This option suggests that deviations from the norm in a plant's growth pattern or flowering characteristics may signal underlying problems. For example, abnormal growth can be caused by stress factors such as nutrient deficiencies, pest infestations, or diseases. Unique flowers, while they might suggest a genetic mutation or hybridization, could also be symptoms of physiological stress or environmental factors affecting the plant.

In contrast, other selections address different aspects. Deformation and tissue discoloration primarily relate to physical damage or disease symptoms but do not encompass the broader range of growth anomalies. High mortality rates among pests pertain to pest control effectiveness rather than plant health issues directly. Finally, the reduction of crop yield is an important consequence of plant issues but isn't a direct characteristic that signals underlying problems the way growth abnormalities are. Thus, the focus on unusual growth habits and flower characteristics stands out as a clear indicator of potential plant issues.