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 many cases the earliest Neolithic sites (approx 4000 - 5000 BC) occur alongside late Mesolithic settlements, or in areas that we know were important in post-glacial times. From the start of the fourth millennium BC (about 3800 BC), we see a move into new areas that had not been settled or exploited previously.