Problem: The most significant event between the 7th and 11th century was the Tripartite struggle centered on Kannauj that lasted for more than two centuries between the Pala Empire, Rashtrakuta Empire, and Gurjara Pratihara Empire. Southern India was ruled by the Chalukya, Chola, Pallava, Chera, Pandyan, and Western Chalukya Empires. The seventh century also saw the advent of Islam as a political power, though as a fringe, in the western part of the subcontinent, in modern-day Pakistan. The Chola dynasty conquered southern India and successfully invaded parts of Southeast Asia, Sri Lanka, Maldives and Bengal in the 11th century. The early medieval period Indian mathematics influenced the development of mathematics and astronomy in the Arab world and the Hindu numerals were introduced.
What facet of Indian mathematics was introduced into the Arab areas in the early Medieval period?
The answer is the following: Hindu numerals

Problem: Synthetic crude oil, also known as syncrude, is the output from a bitumen upgrader facility used in connection with oil sand production in Canada. Bituminous sands are mined using enormous (100 ton capacity) power shovels and loaded into even larger (400 ton capacity) dump trucks for movement to an upgrading facility. The process used to extract the bitumen from the sand is a hot water process originally developed by Dr. Karl Clark of the University of Alberta during the 1920s. After extraction from the sand, the bitumen is fed into a bitumen upgrader which converts it into a light crude oil equivalent. This synthetic substance is fluid enough to be transferred through conventional oil pipelines and can be fed into conventional oil refineries without any further treatment. By 2015 Canadian bitumen upgraders were producing over 1 million barrels (160×10^3 m3) per day of synthetic crude oil, of which 75% was exported to oil refineries in the United States.
What is synthetic crude oil usually called?
The answer is the following: syncrude

Problem: The Alps are a crescent shaped geographic feature of central Europe that ranges in a 800 km (500 mi) arc from east to west and is 200 km (120 mi) in width. The mean height of the mountain peaks is 2.5 km (1.6 mi). The range stretches from the Mediterranean Sea north above the Po basin, extending through France from Grenoble, eastward through mid and southern Switzerland. The range continues toward Vienna in Austria, and east to the Adriatic Sea and into Slovenia. To the south it dips into northern Italy and to the north extends to the south border of Bavaria in Germany. In areas like Chiasso, Switzerland, and Neuschwanstein, Bavaria, the demarcation between the mountain range and the flatlands are clear; in other places such as Geneva, the demarcation is less clear. The countries with the greatest alpine territory are Switzerland, France, Austria and Italy.
How far does the Alps range stretch?
The answer is the following: the Mediterranean Sea north above the Po basin, extending through France from Grenoble, eastward through mid and southern Switzerland

Problem: Modern electrification systems take AC energy from a power grid which is delivered to a locomotive and converted to a DC voltage to be used by traction motors. These motors may either be DC motors which directly use the DC or they may be 3-phase AC motors which require further conversion of the DC to 3-phase AC (using power electronics). Thus both systems are faced with the same task: converting and transporting high-voltage AC from the power grid to low-voltage DC in the locomotive. Where should this conversion take place and at what voltage and current (AC or DC) should the power flow to the locomotive? And how does all this relate to energy-efficiency? Both the transmission and conversion of electric energy involve losses: ohmic losses in wires and power electronics, magnetic field losses in transformers and smoothing reactors (inductors). Power conversion for a DC system takes place mainly in a railway substation where large, heavy, and more efficient hardware can be used as compared to an AC system where conversion takes place aboard the locomotive where space is limited and losses are significantly higher. Also, the energy used to blow air to cool transformers, power electronics (including rectifiers), and other conversion hardware must be accounted for.
What is the main action AC and DC systems have to deal with?
The answer is the following:
converting and transporting