Answer:
A continent is one of seven main divisions of land that make up Earth.
Explanation:
Accurate measurements have been collected for more than a century.
Let's start from the beginning.
<span>Millions and millions of years ago, planet Earth was absolutely crowded with volcanoes. </span>
<span>As you may know, volcanoes release steam and gasses. </span>
<span>As the years went by, the gasses released from volcanoes formed the atmosphere around the planet, which prevented the steam from disappearing into outer space. </span>
<span>The steam eventually, in cycles, began to fall back to Earth. Viola, rain had just been "invented". </span>
<span>As more and more rain fell, considering almost every surface of the planet was volcanic, the water began to build up and "flood" the planet. Many active volcanoes had now been transformed into underwater volcanoes. </span>
<span>As more and more years went by, eventually, bacteria in the water slowly began to evolve, first into jelly-fish like creatures, then tadpole-like creatures, leading all the way up to large ferocious underwater reptiles, amphibians and fish. </span>
<span>As the planet started to warm up, probably by methane gasses released from the prehistoric underwater creatures, the water levels on Earth began to drop again. At the same time, the active underwater volcanoes were creating new landmasses, either by lava cooling on the surface of the water or tectonic plates pushing the volcano above sea level. </span>
<span>So, this, is how fossils of sea creatures ended up in high land-based mountains. </span>
<span>Because millions of years ago, most of Earth was underwater until the water levels dropped or lands "grew" higher. </span>
<span>The Rocky Mountains were once underwater. </span>
<span>If you take a look at images of the Grand Canyon in the United States, you'll see that it resembles the deep caverns and canyons that you find at the bottom of oceans. </span>
<span>That's because the Grand Canyon WAS at the bottom of an ocean.</span>
Answer:
An analysis of 5,000-year-old genetic material from preserved human remains found in Sweden suggests that people moving from southern to northern Europe spread agriculture across that continent long ago.
In addition to agricultural know-how, the intrepid farmers brought their genes: They interbred with hunter-gatherer communities to create modern humans living in Europe today.
"Genetic variation of today's Europeans was strongly affected by immigrant Stone Age farmers, though a number of hunter-gatherer genes remain," study researcher Anders Götherström, of Uppsala University in Sweden, said in a statement.
The results of this study, to be published in the April 27 issue of the journal Science, match up well with previous archeological evidence of farming in Europe.
Explanation:
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