Questions

In the early 20th century, the Balkans were called a "powder keg" because the political situation in the region was very unstable. For a long time, the Ottoman Turks occupied the balkans, and with the rise of nationalism, some balkan states declared independence.

Mount Kilimanjaro

Holland is also known as Netherlands, which means "Low lands". Dutch Engineers reclaimed considerable part of the seabed by building dykes and pumping out the sea water into canals. Some houses in Holland are below sea level. Belgium has also Low lands  bordering the North Sea and dykes are constructed to control the encroachment of the sea.

REM sleep i.e, Rapid Eye Movement sleep is also known as paradoxical sleep because the measures of the brain activity closely resemble waking consciousness, but the person is incapable of moving as the brain is in fully active mode that time.

Tennis rackets and ballpoint pens are two independent goods. Since, one doesn't depend on the other.

Supply curves tend to be more elastic in the long run, because there is time for firms to enter or leave the industry.