Glaciologists, geochemists and climatologists study ice layers to learn about past climates distinct ice layers are
caused
when studying ice layers, scientists
to measure
isotopes of certain gases. these gases reveal
at the time when the ice layers were
formed

B, A, B.

Explanation:

Got it correct, Edge2020.

Distinct ice layers are caused by:  seasonal changes

When studying ice layers, scientists use:  spectrometers

These gases reveal the:  temperature

Explanation:

Answers were taken from the article:  Cool Jobs:  Careers on Ice (Beth Geiger) on page 2 of 4 pages and paragraph 3.

true. earthquakes are felt whenever there is a slip around a fault in the rocks below the earth. this reorientation of faults create sesmic waves and is known as earthquake, the severity of which is measured in richter scale. these are more prominent in hilly regions as the rocks usually form faults to balance the pressures on it.