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.
In the Tigris and Euphrates river valleys, the Neolithic culture of the Middle East developed into the urban civilizations of the Bronze Age by 3500 B.C. Between 6000 B.C. and 2000 B.C. Neolithic culture spread through Europe, the Nile valley (Egypt), the Indus valley (India), and the Huang He valley (N China).