Question: The population of England rose rapidly during the 19th and 20th centuries whereas the populations of Scotland and Wales have shown little increase during the 20th century, with the population of Scotland remaining unchanged since 1951. Ireland for most of its history comprised a population proportionate to its land area (about one third of the total population). However, since the Great Irish Famine, the population of Ireland has fallen to less than one tenth of the population of the British Isles. The famine, which caused a century-long population decline, drastically reduced the Irish population and permanently altered the demographic make-up of the British Isles. On a global scale, this disaster led to the creation of an Irish diaspora that numbers fifteen times the current population of the island.
Is there an answer to this question: During the 17th and 18th centuries, what happened to the population in England?

Answer: unanswerable


Question: Mexico City remains the only Latin American city to host the Olympic Games, having held the Summer Olympics in 1968, winning bids against Buenos Aires, Lyon and Detroit. (This too will change thanks to Rio, 2016 Summer Games host). The city hosted the 1955 and 1975 Pan American Games, the last after Santiago and São Paulo withdrew. The ICF Flatwater Racing World Championships were hosted here in 1974 and 1994. Lucha libre is a Mexican style of wrestling, and is one of the more popular sports throughout the country. The main venues in the city are Arena México and Arena Coliseo.
Is there an answer to this question: What year did Mexico City host the olympics?

Answer: 1968


Question: For the popular taste however, light music, particularly Ghazals and folk songs, which have an appeal of their own, the names of Mehdi Hassan, Ghulam Ali, Nur Jehan, Malika Pukhraj, Farida Khanum, Roshen Ara Begum, and Nusrat Fateh Ali Khan are well-known. Folk songs and dances of the Punjab reflect a wide range of moods: the rains, sowing and harvesting seasons. Luddi, Bhangra and Sammi depict the joy of living. Love legends of Heer Ranjha, Mirza Sahiban, Sohni Mahenwal and Saiful Mulk are sung in different styles.
Is there an answer to this question: What does Heer Ranjha sing about?

Answer: Love


Question: In physics, energy is a property of objects which can be transferred to other objects or converted into different forms. The "ability of a system to perform work" is a common description, but it is difficult to give one single comprehensive definition of energy because of its many forms. For instance, in SI units, energy is measured in joules, and one joule is defined "mechanically", being the energy transferred to an object by the mechanical work of moving it a distance of 1 metre against a force of 1 newton.[note 1] However, there are many other definitions of energy, depending on the context, such as thermal energy, radiant energy, electromagnetic, nuclear, etc., where definitions are derived that are the most convenient.
Is there an answer to this question: What is a property of objects which can be transferred to other objects or converted into different forms?

Answer:
energy