Answer:
External and Internal forces.
Explanation:
The earth's relief forms such as Mountains, Rivers, Plateaus etc, are changed because of the action of internal and external forces for example; wind, water or human activities.
Answer:
every earthquake is recorded on numerous seismographs located in different directions. Knowing this helps them calculate the distance from the epicenter to each seismographs. To determine the direction each wave traveled, scientist draw circles around the seismographs locations
for better research go to under NOAA - Climate.gov
This is a short paraphrased summary of the article about ice cores in that website.
Answer: Researchers in labs may melt or crush bits of the ice core a little at a time, each deeper layer shows the time in the Earth's climate history. Tiny pieces of pollution, metals, radoiactive fallout, pebbles, sea salt, volcanic ash and even air bubbles all present important information that researchers can look for to track changes in the atmosphere's composition and temperature.