What term denotes geographic areas based on average low winter temperatures related to plant adaptability?

The term that denotes geographic areas based on average low winter temperatures related to plant adaptability is "hardiness zone." Hardiness zones are defined by the USDA Plant Hardiness Zone Map, which categorizes regions based on their average annual minimum temperature. This classification helps gardeners and landscapers determine which plants are likely to thrive in their specific geographic area, as it takes into account the ability of plants to withstand cold temperatures during winter.

In contrast, while "climate zone" refers to larger climatic patterns that can encompass various factors like temperature, humidity, and precipitation, it is not specific to plant hardiness. "Growing season" pertains to the period during which plants can grow, influenced by temperature and daylight, but does not specifically address winter temperature limits. "Sun exposure zone" focuses on the amount of sunlight an area receives, which affects plant growth but does not relate directly to cold tolerance or winter temperature averages. Thus, "hardiness zone" is the most precise term for this concept, making it the correct answer.