Problem: Required attendance at school is 10 years for males and 11 years for females (2001). The adult literacy rate is 99.0% (2002). In 2010, there were 1,918 students who were taught by 109 teachers (98 certified and 11 uncertified). The teacher-pupil ratio for primary schools in Tuvalu is around 1:18 for all schools with the exception of Nauti School, which has a teacher-student ratio of 1:27. Nauti School on Funafuti is the largest primary in Tuvalu with more than 900 students (45 percent of the total primary school enrolment). The pupil-teacher ratio for Tuvalu is low compared to the Pacific region (ratio of 1:29).
How many students were in Tuvalu schools in 2010?
The answer is the following: 1,918

Problem: The mantle is equivalent to 10 to 15 Earth masses and is rich in water, ammonia and methane. As is customary in planetary science, this mixture is referred to as icy even though it is a hot, dense fluid. This fluid, which has a high electrical conductivity, is sometimes called a waterammonia ocean. The mantle may consist of a layer of ionic water in which the water molecules break down into a soup of hydrogen and oxygen ions, and deeper down superionic water in which the oxygen crystallises but the hydrogen ions float around freely within the oxygen lattice. At a depth of 7000 km, the conditions may be such that methane decomposes into diamond crystals that rain downwards like hailstones. Very-high-pressure experiments at the Lawrence Livermore National Laboratory suggest that the base of the mantle may comprise an ocean of liquid carbon with floating solid 'diamonds'.
What rains on Neptune?
The answer is the following: diamond crystals

Problem: Official figures (as of July 21, 2008 12:00 CST) stated that 69,197 were confirmed dead, including 68,636 in Sichuan province, and 374,176 injured, with 18,222 listed as missing. The earthquake left about 4.8 million people homeless, though the number could be as high as 11 million. Approximately 15 million people lived in the affected area. It was the deadliest earthquake to hit China since the 1976 Tangshan earthquake, which killed at least 240,000 people, and the strongest in the country since the 1950 Chayu earthquake, which registered at 8.5 on the Richter magnitude scale. It is the 21st deadliest earthquake of all time. On November 6, 2008, the central government announced that it would spend 1 trillion RMB (about US $146.5 billion) over the next three years to rebuild areas ravaged by the earthquake, as part of the Chinese economic stimulus program.
How many people were left homeless because of the earthquake?
The answer is the following: 4.8 million

Problem: Reflections generally affect polarization. For radio waves, one important reflector is the ionosphere which can change the wave's polarization. Thus for signals received following reflection by the ionosphere (a skywave), a consistent polarization cannot be expected. For line-of-sight communications or ground wave propagation, horizontally or vertically polarized transmissions generally remain in about the same polarization state at the receiving location. Matching the receiving antenna's polarization to that of the transmitter can make a very substantial difference in received signal strength.
What reflector can change the waves polarization?
The answer is the following:
ionosphere