The Cretaceous-Tertiary extinction event, or the K-T event, is the name given to the die-off of the dinosaurs and other species that took place some 65.5 million years ago. For many years, paleontologists believed this event was caused by climate and geological changes that interrupted the dinosaurs’ food supply. However, in the 1980s, father-and-son scientists Luis (1911-88) and Walter Alvarez (1940-) discovered in the geological record a distinct layer of iridium–an element found in abundance only in space–that corresponds to the precise time the dinosaurs died. This suggests that a comet, asteroid or meteor impact event may have caused the extinction of the dinosaurs. In the 1990s, scientists located the massive Chicxulub Crater at the tip of Mexico’s Yucatán Peninsula, which dates to the period in question.
Dinosaurs roamed the earth for 160 million years until their sudden demise some 65.5 million years ago, in an event now known as the Cretaceous-Tertiary, or K-T, extinction event. (“K” is the abbreviation for Cretaceous, which is associated with the German word “Kreidezeit.”) Besides dinosaurs, many other species of mammals, amphibians and plants died out at the same time. Over the years, paleontologists have proposed several theories for this extensive die-off. One early theory was that small mammals ate dinosaur eggs, thereby reducing the dinosaur population until it became unsustainable. Another theory was that dinosaurs’ bodies became too big to be operated by their small brains. Some scientists believed a great plague decimated the dinosaur population and then spread to the animals that feasted on their carcasses. Starvation was another possibility: Large dinosaurs required vast amounts of food and could have stripped bare all the vegetation in their habitat. But many of these theories are easily dismissed. If dinosaurs’ brains were too small to be adaptive, they would not have flourished for 160 million years. Also, plants do not have brains nor do they suffer from the same diseases as animals, so their simultaneous extinction makes these theories less plausible.
The Proclamation of 1763 limited the colonies from expanding west of the Appalachian Mountains. King George III of Britain proclaimed that all lands west of the Appalachian Mountain Region were uninhabitable for colonial settlers and reserved for Indigenous Americans.
Answer:selection
Explanation:
Selection occurs when subjects who may be unrelated but have similar variables or factors and because of those similar features each oneauve be mistake for the other one.
A person may recognise someone as familiar only because the person their are familiar with Also has the same hair cut and shape of the head or even their height is the same as a result of these similar features the one may be mistaken for the other.
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Answer:
4 Important Factors To Consider Before Investing
Risk Vs Reward. Any kind of investment would involve a certain degree of risk. ...
Individual Risk Appetite. One man's food is another man's poison – the same goes for investment. ...
Investment Capital. The amount is investment capital you have can also affect your choice of investment. ...
Time Horizon.
