Scientists hypothesize that the K – Pg extinctions were caused by one or more catastrophic events, including at least one asteroid impact ( especially the one that created the Chicxulub crater ) or increased volcanic activity.

Scientists hypothesize that some of the first water brought to Earth was delivered by asteroid impacts after the collision that produced the Moon.

Scientists hypothesize that sufficient volcanic interaction with the lake's bottom water that has high gas concentrations would heat water, force the methane out of the water, spark a methane explosion, and trigger a nearly simultaneous release of carbon dioxide.

Scientists hypothesize that increased cephalization in vertebrates, including the evolution of many of their novel head features, is related to adaptations for predation.

Scientists do not know a lot about this species, but they hypothesize that the African manatee is very similar to the West Indian manatee ( Trichechus manatus ).

Scientists dismiss these mechanisms as implausible since, for example, the magnetic field, when measured from earth, of a large but distant planet such as Jupiter is far smaller than that produced by ordinary household appliances.

Scientists theorise that these organisms survived the collapse of plant-based food chains because they fed on detritus .< ref name =" SheehanHansen ">

Scientists currently think that cnidarians, ctenophores and bilaterians are more closely related to calcareous sponges than these are to other sponges, and that anthozoans are the evolutionary " aunts " or " sisters " of other cnidarians, and the most closely related to bilaterians.

The day before Hilbert pronounced these phrases at the 1930 annual meeting of the Society of German Scientists and Physicians, Kurt Gödel — in a roundtable discussion during the Conference on Epistemology held jointly with the Society meetings — tentatively announced the first expression of his incompleteness theorem.

Scientists have resolved many of these questions decisively in favour of the view that the warming trend is unprecedented, that human activity is the primary cause and that it has been accurately measured.

Scientists were unable to prepare compounds of argon until the end of the 20th century, but these attempts helped to develop new theories of atomic structure.

Scientists include theoreticians who mainly develop new models to explain existing data and predict new results, and experimentalists who mainly test models by making measurements — though in practice the division between these activities is not clear-cut, and many scientists perform both tasks.

Dr. Bashir Syed, former president of the Association of Pakistani Scientists and Engineers of North America ( APSENA ), said: " I know both of these persons and can tell you there is not an iota of truth that both these respected scientists and friends will do anything to harm the interest of their own country.

Scientists tend to use thought experiments in the form of imaginary, " proxy " experiments which they conduct prior to a real, " physical " experiment ( Ernst Mach always argued that these gedankenexperiments were " a necessary precondition for physical experiment ").

Scientists also use thought experiments when particular physical experiments are impossible to conduct ( Carl Gustav Hempel labeled these sorts of experiment " theoretical experiments-in-imagination "), such as Einstein's thought experiment of chasing a light beam, leading to Special Relativity.

Scientists, conservationists, fishermen, and governments around the world are working to reduce the threats posed to them, and these efforts have led to the signing of the Agreement on the Conservation of Albatrosses and Petrels, a legally binding international treaty signed in 2001.

Scientists in this field conduct research concerned with understanding the interactions between the various systems of a cell, including the interactions between DNA, RNA and protein biosynthesis, as well as how these interactions are regulated.

Scientists were confident that an implosion device would work, but these new design difficulties were great.

Scientists who want to use the telescope submit proposals, and these are evaluated by an independent scientific board.

Scientists speculate that the coevolution of these two species could have begun 60 – 70 million years ago.

Scientists continue to search for the causes of these earthquakes, and especially for some indication of how often they recur.

Scientists may make claims about unobservable objects, but these claims should not be regarded as meaningful.

Scientists now believe that there are a wide variety of voltage-sensitive currents, and the implications of the differing dynamics, modulations and sensitivity of these currents is an important topic of computational neuroscience.

Scientists tend to refer to these birds as " parrots " or " parakeets.

Scientists at Goddard work closely with the engineers to develop these instruments.

Also in 2004, the scientific advocacy group Union of Concerned Scientists issued a report, Scientific Integrity in Policymaking: An Investigation into the Bush Administration's Misuse of Science which charged the following: " A growing number of scientists, policy makers, and technical specialists both inside and outside the government allege that the current Bush administration has suppressed or distorted the scientific analyses of federal agencies to bring these results in line with administration policy.

Scientists have found that the flow of these glaciers has increased in recent years, if they were to melt completely global sea levels would rise by about 0. 9 – 1. 9 m ( 1 – 2 yards ).

Scientists have used these dental characteristics to identify Compsognathus and its closest relatives.

Scientists have genetically engineered several organisms, including some mammals, to include green fluorescent protein ( GFP ) for medical research purposes ( Chalfie, Shimoura, and Tsien were awarded the Nobel prize in 2008 for GFP ).

Scientists once thought that organic compounds are or could only be created by living organisms.

Scientists first discovered that DNA can transfer between organisms in 1946.

Scientists who do experimental genetics employ artificial selection experiments that permit the survival of organisms with user-defined phenotypes.

Scientists believe that when they understand more about how organisms evolved the capacity to acclimate, they will better understand acclimation.

Scientists have been attempting to artificially petrify organisms as early as the 18th century, when Girolamo Segato succeeded in artificially petrifying human remains.

Scientists associated with the initial development of recombinant DNA methods recognized that the potential existed for organisms containing recombinant DNA to have undesirable or dangerous properties.

Scientists first discovered that DNA naturally transfers between organisms in 1946.

Scientists have also suggested that the discovery of the flute may help to explain why early humans survived, while Neanderthals became extinct.

Scientists also note that HIV-negative drug users do not suffer from immune system collapse.

Scientists believed it was triggered by a partial collapse of the lava dome.

Scientists aim to discover what goes on inside barley grains as they become malted to help plant breeders produce better malting barley for food and beverage products.

Scientists who had obtained a doctorate ( a post-Ph. D. degree under the Russian system ) were rewarded by the authorities with the special food delivery service (" doktorskiy zakaz ”), which provided access to a wider selection of groceries than available to the general population ; some of the scientists, despite being eligible, refused it on moral grounds.

Scientists are continually researching new aspects of frozen food packaging.

Scientists at the University of Sussex showed in 2009 that purring, or some purring, seems to be a way for domesticated cats to signal their owners for food.

< http :// proquest. umi. com. www. library. gatech. edu: 2048 / pqdweb? did = 1000187651 & Fmt = 4 & VInst = PROD & VType = PQD & RQT = 309 & VName = PQD &>.</ ref > Scientists believe that food moves quickly through the digestive tract of M. grisescens, with feces being purged from the body within 1 – 2 hours prior to ingestion .< ref > Best, T. L., B. A. Milam, T. D.

Scientists believe this was advantageous because it allowed for the evolution of more effective mouth-parts for capturing and processing food.

Scientists believe Weddell seals rely mainly on eyesight to hunt for food when light is available.

Scientists have been working to find ways to reduce contamination of food using a method called the ' multiple-barrier approach '.