Final answer:
Glacial episodes exemplify positive feedback in climatic systems, as melting ice leads to more warming and further ice melt acceleration.
Step-by-step explanation:
Glacial episodes are an example of positive feedback in the context of Earth's climate system. Positive feedback loops occur when an initial change in a system leads to further changes that exacerbate the initial one.
An example of this is when glacial melting reduces the amount of sunlight reflected back into space due to the decrease in ice cover, leading to increased warming and more ice melting.
This is different from negative feedback, which tends to stabilize a system, such as the way plants use various mechanisms to maintain their internal environments in response to external changes.