Answer:
C. changes in temperature
Step-by-step explanation:
The deciduous trees are the trees that shed their leaves in the autumn, and also minimize their activity during the winter months, starting to be active and grow new leaves in the spring. The main reason for this action by this type of trees is the temperature. The temperature in the winters is very low, often being far beyond the freezing point, making it very difficult for these trees to survive if they are active through it. In order to avoid severe damage or dying out in the winter, these plants hibernate, but also have developed thick bark, and very resilient roots.