QUES: By 3400 BCE, the Sahara was as dry as it is today, due to reduced precipitation and higher temperatures resulting from a shift in the Earth's orbit. As a result of this aridification, it became a largely impenetrable barrier to humans, with the remaining settlements mainly being concentrated around the numerous oases that dot the landscape. Little trade or commerce is known to have passed through the interior in subsequent periods, the only major exception being the Nile Valley. The Nile, however, was impassable at several cataracts, making trade and contact by boat difficult.

By What time period was the Sahara dry like it is today?
What is the answer?
ANS: 3400 BCE
QUES: In 1902, the Siemens company developed a tantalum lamp filament. These lamps were more efficient than even graphitized carbon filaments and could operate at higher temperatures. Since tantalum metal has a lower resistivity than carbon, the tantalum lamp filament was quite long and required multiple internal supports. The metal filament had the property of gradually shortening in use; the filaments were installed with large loops that tightened in use. This made lamps in use for several hundred hours quite fragile. Metal filaments had the property of breaking and re-welding, though this would usually decrease resistance and shorten the life of the filament. General Electric bought the rights to use tantalum filaments and produced them in the US until 1913.

What company invented the tantalum light filament?
What is the answer?
ANS: Siemens
QUES: Although research has been inconclusive, some findings have indicated that electronic communication negatively affects adolescents' social development, replaces face-to-face communication, impairs their social skills, and can sometimes lead to unsafe interaction with strangers. A 2015 review reported that "adolescents lack awareness of strategies to cope with cyberbullying, which has been consistently associated with an increased likelihood of depression." Studies have shown differences in the ways the internet negatively impacts the adolescents' social functioning. Online socializing tends to make girls particularly vulnerable, while socializing in Internet cafes seems only to affect boys academic achievement. However, other research suggests that Internet communication brings friends closer and is beneficial for socially anxious teens, who find it easier to interact socially online. The more conclusive finding has been that Internet use has a negative effect on the physical health of adolescents, as time spent using the Internet replaces time doing physical activities. However, the Internet can be significantly useful in educating teens because of the access they have to information on many various topics.

Which online activity has been consistently associated with increased liklihood of depression?
What is the answer?
ANS:
cyberbullying