Observed throughout the animal kingdom, courtship is the practice of wooing a member of the opposite sex with the ultimate goal of mating. Animal courtship may involve complicated dances or touching; vocalizations; or displays of beauty or fighting prowess. Humans, meanwhile, have evolved elaborate courtship rituals involving flowers, gifts, songs, poetry, restaurants, and various displays of affection. How has online dating changed traditional courtship roles? Discuss
Source: The Free Dictionary
Located in Cairo, Egypt, Al-Azhar University was founded in 972 CE as a madrasa—a place of Islamic learning. By teaching numerous subjects in the same place, it was one of the first universities in the world and the only one to survive as a modern university. Historically, students primarily studied the Qur’an and Islamic law. Today, the university is the world’s chief center of Arabic literature and Islamic learning. When did it begin teaching a wide range of secular subjects? 
XYY syndrome is a chromosomal anomaly characterized by the presence of one X-chromosome and two Y-chromosomes. Some medical geneticists question whether the term “syndrome” is appropriate for this sex-linked trisomy, because afflicted males are physically normal—though they tend to be above average in height—and the vast majority of those affected do not know that they possess the extra chromosome. About 1 in 1,000 boys are born with this condition. How does the chromosomal disorder develop? 
As storm clouds develop, the temperature at the top of the clouds becomes much cooler than that at the bottom. For reasons that scientists still do not understand, this temperature difference results in the accumulation of negatively charged particles near the base and positively charged particles near the top of the storm cloud. This buildup of electrical charge causes a high-voltage discharge in the form of lightning. What is sheet lightning, and how does it differ from forked lightning? 
A labyrinth is an intricate building of chambers and interconnecting passages often constructed so as to perplex and confuse a person inside. The most celebrated structure of this sort was designed, according to Greek mythology, by the Athenian artisan Daedalus to confine the Minotaur, a monster with a bull’s head and a man’s body. Theseus, an Athenian hero, entered the beast’s labyrinth to slay it. How did he find his way out of the maze after killing the Minotaur? 
Electroconvulsive therapy (ECT) is a therapeutic treatment in which an electric current is passed through the brain, inducing seizures and alterations in the brain’s electrical activity. It is used to treat certain mental disorders and is generally employed only after other therapies have proven ineffective. ECT can cause memory loss and bone fractures, and there is much controversy surrounding its use and effectiveness. Who are some of the noted actors and writers who have undergone ECT? 
In his observations of World War I veterans, Sigmund Freud noticed that the men had a strange proclivity toward reenacting traumatic experiences. He also observed this tendency in young children who often play games that simulate unpleasant situations. To explain this, he introduced and later developed the concept of the death drive: a primitive impulse for destruction, decay, and death, manifested by a turning away from pleasure. What Freudian principle does the death drive violate? 
The use of the fork is a basic concern of Western table etiquette. The utensil’s origin is disputed; certain passages in the book of I Samuel suggest that forks were used during priestly sacrifice, and it is commonly accepted that the Greeks used serving forks long before the Middle Ages. Before the fork made its 10th century debut at tables across Europe, people commonly used their hands to eat. Why did the Roman Catholic Church initially consider the use of a fork an insult to God? 
Music existed long before human cultures were literate or had developed a written system of record-keeping, perhaps originating as an attempt to echo the sounds and rhythms of nature. These sounds may have been used to lure prey while hunting or in recreational or shamanistic rituals. The oldest known bone flute is about 50,000 years old, but experts believe that humans may have used what to create a form of music that predates such instruments? 
Fire-eaters are entertainers who extinguish flaming objects and transfer flames using their mouths and other body parts. The tradition of fire-eating was embedded in the spiritual performances of Hindu ascetics, and by the late 1880s, these daring acts had become a standard element in sideshow productions. Extinguishing tricks are the traditional hallmark of fire-eating, and performers often use their mouths to snuff out 1, 2, or even 3 flaming torches. What is the “secret” to fire-eating?