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.
By contrast, Agriculture in the Nile River Valley developed the original Neolithic Revolution in the Fertile Crescent. Many grinding stones are found with the early Egyptian Sebilian and Mechian cultures and evidence has been found of a neolithic domesticated crop-based economy dating around 7,000 BP.