Chapter 490 Instruments

After strolling around for another round, Chu Yu was also a little confused.

Chu Yu looked at Bai Yue, "This Yili... No, these nine circles existed before?"

"No." Bai Yue shook her head and said, "There were satellite photos taken thirty-six hours ago. It was definitely not like this now. I saw the photos with my own eyes."

"What caused that?"

"Normally, the driving force for landform change comes from two aspects," Dracula said, crossing his arms. "The first reason is from the interior of the earth, which refers to the crustal movement and magma activity caused by the earth's internal energy. The second reason is from external forces, such as the various effects of solar energy and gravity on the earth's surface, such as weathering, flowing water, glaciers, ocean currents, waves and tides, and wind erosion, transportation and sedimentation."

After a pause, Dracula continued, "Internal forces create the basic outline of the earth's surface, that