Answer:
1. By studying ice they can tell scientists about temperature, precipitation, atmospheric composition, volcanic activity, and even wind patterns.
2. Floraminifera shells are composed of calcium carbonate (CaCO3) and are found in many common geological environments. The ratio of 18O to 16O in the shell is used to indirectly determine the temperature of the surrounding water at the time the shell was formed.
3. Fossilized pollen grains are an important kind of data for reconstructing past vegetation. Because vegetation is sensitive to climate, the findings of fossil pollen is a very important kind of proxy data for reconstructing past climates.
4. Tree rings usually grow wider in warm, wet years and they are thinner in years when it is cold and dry. If the tree has experienced stressful conditions, such as a drought, the tree might hardly grow at all in those years.
Explanation:
1. The ice traps the atmospheric conditions in layers. Chemical composition can tell us when colder temperatures lead to a higher concentration of a particular oxygen isotope in the snow. The icy layers also hold particles—aerosols such as dust, ash, pollen, trace elements and sea salts—that were in the atmosphere at that time.
