Final answer:
The dependent variable in an experiment examining the change in glacial recession over time is the extent or size of the glacial recession.
Step-by-step explanation:
The dependent variable in an experiment examining the change in glacial recession over time would be the extent or size of the glacial recession. It is the variable that will be measured and is expected to change in response to the independent variable, which would be the time period. By comparing the extent of glacial recession over different time periods, scientists can observe and analyze the changes in glacial cover.