What is the best example of how an advance in the use of technology made life less difficult for Paleolithic people? Multiple choice question.

Which of the following was probably the most difficult challenge facing construction of the railroad?

What ideas, institution, and causes became the focal points of chinese and islamic resistance respectively to the west in the latter half of 19th century and the first decades of the 20th

20 points “the creation of a mosaic was a complicated procedure that called for careful timing and teamwork. . walls were painted with resin or tar before being covered with the first of three layers of plaster. . a sketch of the projected work was then made on the plaster to serve as a guide for the various artisans. the outermost layer of plaster, in which the pieces, or tesserae, of the mosaic would be set, was spread on only enough area to contain a day’s work. some of the tesserae—small, carefully cut fragments of colored glass, marble, and semiprecious stones—were pressed into the wet plaster so that they projected at a slight angle. the stones thereby better reflected light and imbued the finished mosaic with a shimmering life of its own.” —empires besieged: time frame a. d. 200–600 how many layers of materials were under the tiles? a. two- c. four- b. three- d. five