Important changes in the Middle East between the 13th and 15th centuries include the 13 Century end of the First Crusade and the capture/founding of Jerusalem. After that came the rise of the Mongol/Turkish/Ottoman Empire during the 14th Century. The Ottoman transcontinental Empire controlled much of North Africa, Western Asia, and Southeast Europe. This led to the creation of important transcontinental trade routes and a boom of economic trade between the continents.
Pushing the Mongols north and fighting them, and the rebuilding of Beijing caused the Chinese decision to abandon major expeditions.
The answer for you question is this:
B)Schist
Explanation:
The frictional resistance of the various pipes are given by the
K value in the table which may be used with the formula
hf = KQ2
to relate the magnitude of head loss hf in the pipeline
to the volumetric flow rate, Q. Water is drawn at the constant flow
rates from the network at nodes C and D. The static heads
(elevation + pressure head) at nodes B, C and D are 100m, 65m
and 61m respectively above the local datum. Calculate the
discharges at C and D and the water level in reservoir A. (The
data has been added to the diagram to aid the solution)
Use no more than 3 iterations and 3 significant figures.
The chants can be sung by using six-note patterns called hexachords. Gregorian melodies are traditionally written using neumes, an early form of musical notation from which the modern four-line and five-line staff developed. Good luck!!