QUES: The Sumerian city-states rose to power during the prehistoric Ubaid and Uruk periods. Sumerian written history reaches back to the 27th century BC and before, but the historical record remains obscure until the Early Dynastic III period, c. the 23rd century BC, when a now deciphered syllabary writing system was developed, which has allowed archaeologists to read contemporary records and inscriptions. Classical Sumer ends with the rise of the Akkadian Empire in the 23rd century BC. Following the Gutian period, there is a brief Sumerian Renaissance in the 21st century BC, cut short in the 20th century BC by Semitic Amorite invasions. The Amorite "dynasty of Isin" persisted until c. 1700 BC, when Mesopotamia was united under Babylonian rule. The Sumerians were eventually absorbed into the Akkadian (Assyro-Babylonian) population.

During what periods did the Sumerican city-states rise to power?
What is the answer?
ANS: prehistoric Ubaid and Uruk
QUES: The currentvoltage characteristic of an LED is similar to other diodes, in that the current is dependent exponentially on the voltage (see Shockley diode equation). This means that a small change in voltage can cause a large change in current. If the applied voltage exceeds the LED's forward voltage drop by a small amount, the current rating may be exceeded by a large amount, potentially damaging or destroying the LED. The typical solution is to use constant-current power supplies to keep the current below the LED's maximum current rating. Since most common power sources (batteries, mains) are constant-voltage sources, most LED fixtures must include a power converter, at least a current-limiting resistor. However, the high resistance of three-volt coin cells combined with the high differential resistance of nitride-based LEDs makes it possible to power such an LED from such a coin cell without an external resistor.

What feature do most LED fixtures need to have?
What is the answer?
ANS: a power converter
QUES: The context-sensitive button mechanic allows one button to serve a variety of functions, such as talking, opening doors, and pushing, pulling, and throwing objects.[e] The on-screen display shows what action, if any, the button will trigger, determined by the situation. For example, if Link is holding a rock, the context-sensitive button will cause Link to throw the rock if he is moving or targeting an object or enemy, or place the rock on the ground if he is standing still.[f]

What mechanic allows one button to serve many functions?
What is the answer?
ANS:
context-sensitive button mechanic