In-facepiece dust concentration is changed dozens of times in a matter of minutes due to changes of the size of the gaps between the mask and face. Source. A respirator is a device designed to protect the wearer from inhaling particulate matter, including airborne microrganisms, fumes, vapors, i.e. gases.
Why join Brainly? A community for students. Products of the neolithic culture Steel plows Boats with sails Domesticated dogs Wild figs. the answer would mostly likely be referring to things that actually were of use to the neolithic people and agriculture was the biggest thing making the answer steel plow. anonymous.
At minimum, the Xia period marked an evolutionary stage between the late neolithic cultures and the typical Chinese urban civilization of the Shang dynasty. The Dawn of History Thousands of archaeological finds in the Huang He (), Henan Valley () --the apparent cradle of Chinese civilization--provide evidence about the Shang dynasty, which endured roughly from 1700 to 1027 B.C.