In the east, the Ural Mountains separate Europe from Asia. The nations of Russia and Kazakhstan straddle both continents.
That is called a mineral. Hope this helped.
Modern, human-caused climate change is escalating the threats that make sea walls necessary. Sea levels are rising, putting communities at greater risk from floods. Storms are intensifying, causing more and more sand to erode from beaches.
"The Silurian is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at 443.8 million years ago, to the beginning of the Devonian Period, 419.2 Mya.<span> <span>Wikipedia."
https://www.google.com/search?q=He+Silurian+period+occurred&rlz=1C1RUCY_enUS760US760&oq=He+Silurian+...
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