Answer:
Step-by-step explanation:
Air bubbles and dust get trapped in ice as it forms. And the ice in some places, like Antarctica, has stayed frozen for over a million years. Scientists drill holes in the ice and remove ice cores. Each year's worth of ice forms a layer within the core.
The material trapped in ice layers gives information about the climate at that time. Scientists study the layers to learn about past temperatures and precipitation. They can learn how the amount of carbon dioxide in the atmosphere has changed over time. The layers also reveal when events such as volcanic eruptions have taken place.