Question

about 20,000 years ago, when changes in earths orbit ______ summer sunshine over the giant ice sheets

decreased

increased

rewatch

Explanation:

About 20,000 years ago, during the last glacial maximum, changes in Earth's orbit (Milankovitch cycles) led to a decrease in summer sunshine over the giant ice sheets, which contributed to the growth of ice sheets. So the correct option is the one with "decreased".

Answer:

decreased (the option with the text "decreased")