Article: Predators are often another organism's prey, and likewise prey are often predators. Though blue jays prey on insects, they may in turn be prey for cats and snakes, and snakes may be the prey of hawks. One way of classifying predators is by trophic level. Organisms that feed on autotrophs, the producers of the trophic pyramid, are known as herbivores or primary consumers; those that feed on heterotrophs such as animals are known as secondary consumers. Secondary consumers are a type of carnivore, but there are also tertiary consumers eating these carnivores, quartary consumers eating them, and so forth. Because only a fraction of energy is passed on to the next level, this hierarchy of predation must end somewhere, and very seldom goes higher than five or six levels, and may go only as high as three trophic levels (for example, a lion that preys upon large herbivores such as wildebeest, which in turn eat grasses). A predator at the top of any food chain (that is, one that is preyed upon by no organism) is called an apex predator; examples include the orca, sperm whale, anaconda, Komodo dragon, tiger, lion, tiger shark, Nile crocodile, and most eagles and owls—and even omnivorous humans and grizzly bears. An apex predator in one environment may not retain this position as a top predator if introduced to another habitat, such as a dog among alligators, a skunk in the presence of the great horned owl immune to skunk spray, or a snapping turtle among jaguars; a predatory species introduced into an area where it faces no predators, such as a domestic cat or a dog in some insular environments, can become an apex predator by default.

Question: What is the the strata of predator prey interaction called?
Ans: trophic level


Article: Freedom of the press is ostensibly officially guaranteed by the government, but independent press outlets remain restricted, as does a substantial amount of web content. According to the Institute for War & Peace Reporting, access is blocked to local and foreign websites including avesta.tj, Tjknews.com, ferghana.ru, centrasia.ru and journalists are often obstructed from reporting on controversial events. In practice, no public criticism of the regime is tolerated and all direct protest is severely suppressed and does not receive coverage in the local media.

Question: What is not tolerated by the government in respect to media?
Ans: no public criticism of the regime is tolerated


Article: These developments led to the theory of conservation of energy, formalized largely by William Thomson (Lord Kelvin) as the field of thermodynamics. Thermodynamics aided the rapid development of explanations of chemical processes by Rudolf Clausius, Josiah Willard Gibbs, and Walther Nernst. It also led to a mathematical formulation of the concept of entropy by Clausius and to the introduction of laws of radiant energy by Jožef Stefan. According to Noether's theorem, the conservation of energy is a consequence of the fact that the laws of physics do not change over time. Thus, since 1918, theorists have understood that the law of conservation of energy is the direct mathematical consequence of the translational symmetry of the quantity conjugate to energy, namely time.

Question: What states that the conservation of energy is a consequence of the fact that the laws of physics do not change over time?
Ans: Noether's theorem


Article: Between 1945 and 1989, the share of ethnic Estonians in the population resident within the currently defined boundaries of Estonia dropped to 61%, caused primarily by the Soviet programme promoting mass immigration of urban industrial workers from Russia, Ukraine, and Belarus, as well as by wartime emigration and Joseph Stalin's mass deportations and executions.[citation needed] By 1989, minorities constituted more than one-third of the population, as the number of non-Estonians had grown almost fivefold.

Question: What period did the amount of ethnic Estonians drop by 61%?
Ans:
Between 1945 and 1989