What is one of zhou dynasty achievements

Technician a says that the sine with dwell (swd) test is used to determine if an electronic stability control system functions normally. technician b says that the esc lamp, called a telltale light, is required to remain on for two minutes. who is correct?

Describe the technology advancements that lead to explorers being able to sail great distances. [[ps: doesn't explain where. i am only speculating it's in europe.

According to the map, most mining occurs in the a.northern b.southern c.eastern d.western