 
 <prompt> ```Which one best describe how ice cores dey important to di study of geologic history?

[a]. Dem show unconformities, wey dey signal changes for deposition.
[b]. Dem hold index fossils, wey dem dey use to date di different ice cores.
[c]. Dem contain evidence wey show changes for di atmospheric composition over time.
[d]. Dem follow di Law of Superposition, wey dey give reasons for extinctions of species.``` <response>: ```[c].``` 