Oxygen-18 and oxygen-16 are useful in studying the geologic past,including gathering information about past climate,because ____________.
A) ozone formation and decay depend on the ratio of oxygen-18 to oxygen-16
B) both water and calcite contain oxygen
C) ice and plankton skeletons are often found in layers that geologists can age-date.
D) Both b and c are correct.

Question

Quizplus · Accepted Answer

Both water and calcite contain oxygen, and oxygen-18 and oxygen-16 can be analyzed in them to gather information about past climate. Additionally, ice and plankton skeletons containing oxygen-18 and oxygen-16 are often found in layers that geologists can age-date, providing further insight into the geologic past. Ozone formation and decay do involve oxygen isotopes, but this is not the primary reason why oxygen-18 and oxygen-16 are useful in studying the geologic past.

Oxygen-18 and Oxygen-16 Are Useful in Studying the Geologic Past,including