After Retrieving a Core,the Layers May Be Analyzed in Two

After retrieving a core,the layers may be analyzed in two ways.First,scientists study the presence or absence and fluctuations of different foraminiferan species.Second,using a mass spectrometer,they analyze the

A) fluctuations in the ratio of stable oxygen isotopes 18 and 16 in the calcium carbonate of the foraminiferan shells
B) fluctuations in the ratio of nitrogen isotopes 15 and 14 in the calcium carbonate of the foraminiferan shells
C) fluctuations in the ratio of pollens to foraminifera through time
D) fluctuations in the amino acids of bone collagen in the foraminifera
E) all of the above