QUES: Successful cultivation of cotton requires a long frost-free period, plenty of sunshine, and a moderate rainfall, usually from 600 to 1,200 mm (24 to 47 in). Soils usually need to be fairly heavy, although the level of nutrients does not need to be exceptional. In general, these conditions are met within the seasonally dry tropics and subtropics in the Northern and Southern hemispheres, but a large proportion of the cotton grown today is cultivated in areas with less rainfall that obtain the water from irrigation. Production of the crop for a given year usually starts soon after harvesting the preceding autumn. Cotton is naturally a perennial but is grown as an annual to help control pests. Planting time in spring in the Northern hemisphere varies from the beginning of February to the beginning of June. The area of the United States known as the South Plains is the largest contiguous cotton-growing region in the world. While dryland (non-irrigated) cotton is successfully grown in this region, consistent yields are only produced with heavy reliance on irrigation water drawn from the Ogallala Aquifer. Since cotton is somewhat salt and drought tolerant, this makes it an attractive crop for arid and semiarid regions. As water resources get tighter around the world, economies that rely on it face difficulties and conflict, as well as potential environmental problems. For example, improper cropping and irrigation practices have led to desertification in areas of Uzbekistan, where cotton is a major export. In the days of the Soviet Union, the Aral Sea was tapped for agricultural irrigation, largely of cotton, and now salination is widespread.
Why is cotton grown as an annual crop?

ANS: control pests

QUES: There are two major mechanical pulps, the thermomechanical one (TMP) and groundwood pulp (GW). In the TMP process, wood is chipped and then fed into large steam heated refiners, where the chips are squeezed and converted to fibres between two steel discs. In the groundwood process, debarked logs are fed into grinders where they are pressed against rotating stones to be made into fibres. Mechanical pulping does not remove the lignin, so the yield is very high, >95%, however it causes the paper thus produced to turn yellow and become brittle over time. Mechanical pulps have rather short fibres, thus producing weak paper. Although large amounts of electrical energy are required to produce mechanical pulp, it costs less than the chemical kind.
Besides the thermomechanical process, what is a process not used in pulping?

ANS: unanswerable

QUES: Heartwood is often visually distinct from the living sapwood, and can be distinguished in a cross-section where the boundary will tend to follow the growth rings. For example, it is sometimes much darker. However, other processes such as decay or insect invasion can also discolor wood, even in woody plants that do not form heartwood, which may lead to confusion.
What is the living wood in a tree called?

ANS: sapwood

QUES: Some critics object to materialism as part of an overly skeptical, narrow or reductivist approach to theorizing, rather than to the ontological claim that matter is the only substance. Particle physicist and Anglican theologian John Polkinghorne objects to what he calls promissory materialism claims that materialistic science will eventually succeed in explaining phenomena it has not so far been able to explain. Polkinghorne prefers "dual-aspect monism" to faith in materialism.
Instead of faith, John Polkinghorne relies on what when it comes to the theory of materialism?

ANS:
dual-aspect monism