Based on the graph on ice cores, we can conclude that A. Earth’s climate responds to changes in greenhouse gas levels.
What does the graph on ice cores show?
It shows that the amount of carbon dioxide in the atmosphere over the years, have shown that they can influence the ice cores in the planet.
This means that greenhouse gases (carbon dioxide for instance) have an impact on the earth's climate which was why there was a change in ice cores.
In conclusion, option A is correct.
Find out more on ice cores at https://brainly.com/question/23668225.