Problem: Compact disc:

A CD is read by focusing a 780 nm wavelength (near infrared) semiconductor laser housed within the CD player, through the bottom of the polycarbonate layer. The change in height between pits and lands results in a difference in the way the light is reflected. By measuring the intensity change with a photodiode, the data can be read from the disc. In order to accommodate the spiral pattern of data, the semiconductor laser is placed on a swing arm within the disc tray of any CD player. This swing arm allows the laser to read information from the centre to the edge of a disc, without having to interrupt the spinning of the disc itself.

What createds the change in light reflected off of a CD?
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A: change in height between pits and lands

Problem: Southampton had an estimated 236,900 people living within the city boundary in 2011. There is a sizeable Polish population in the city, with estimates as high as 20,000.
What nationality of people makes up a large portion of Southampton residents?
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Answer: Polish

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Plymouth's gross value added (a measure of the size of its economy) was 5,169 million GBP in 2013 making up 25% of Devon's GVA. Its GVA per person was 19,943 and compared to the national average of 23,755, was 3,812 lower. Plymouth's unemployment rate was 7.0% in 2014 which was 2.0 points higher than the South West average and 0.8 points higher than the average for Great Britain (England, Wales and Scotland).
What was Plymouth's 2013 GVA in millions of British Pounds?
A: 5,169

Context and question: Double fertilization refers to a process in which two sperm cells fertilize cells in the ovary. This process begins when a pollen grain adheres to the stigma of the pistil (female reproductive structure), germinates, and grows a long pollen tube. While this pollen tube is growing, a haploid generative cell travels down the tube behind the tube nucleus. The generative cell divides by mitosis to produce two haploid (n) sperm cells. As the pollen tube grows, it makes its way from the stigma, down the style and into the ovary. Here the pollen tube reaches the micropyle of the ovule and digests its way into one of the synergids, releasing its contents (which include the sperm cells). The synergid that the cells were released into degenerates and one sperm makes its way to fertilize the egg cell, producing a diploid (2n) zygote. The second sperm cell fuses with both central cell nuclei, producing a triploid (3n) cell. As the zygote develops into an embryo, the triploid cell develops into the endosperm, which serves as the embryo's food supply. The ovary now will develop into fruit and the ovule will develop into seed.
What type of cell travels down the pollen tube while it's growing?
Answer: haploid generative

Question: The University of Bath and Bath Spa University are higher education establishments in the north-east of the county. The University of Bath gained its Royal Charter in 1966, although its origins go back to the Bristol Trade School (founded 1856) and Bath School of Pharmacy (founded 1907). It has a purpose-built campus at Claverton on the outskirts of Bath, and has 15,000 students. Bath Spa University, which is based at Newton St Loe, achieved university status in 2005, and has origins including the Bath Academy of Art (founded 1898), Bath Teacher Training College, and the Bath College of Higher Education. It has several campuses and 5,500 students.
Is there an answer to this question: What University are in Bath

Answer: The University of Bath and Bath Spa University are higher education establishments in the north-east of the county

Question: Insects are the only invertebrates to have developed active flight capability, and this has played an important role in their success.:186 Their muscles are able to contract multiple times for each single nerve impulse, allowing the wings to beat faster than would ordinarily be possible. Having their muscles attached to their exoskeletons is more efficient and allows more muscle connections; crustaceans also use the same method, though all spiders use hydraulic pressure to extend their legs, a system inherited from their pre-arthropod ancestors. Unlike insects, though, most aquatic crustaceans are biomineralized with calcium carbonate extracted from the water.
Is there an answer to this question: Insects are also known as what kind of vertebra?

Answer:
invertebrates