How did scientists learn that
climates howe Changes in the past?

Explanation:

To extend those records, paleoclimatologists look for clues in Earth's natural environmental records. Clues about the past climate are buried in sediments at the bottom of the oceans, locked away in coral reefs, frozen in glaciers and ice caps, and preserved in the rings of trees.

d. new methods of assembly are introduced.

explanation:

this allows for the goods to be made on a larger scale. not faster because now it is shown to be made better, hence the greater productivity in the question. it is calling for something new to be introduced.

answerpeople organize large projects such as levee-building;