Because of increasing sea ice.
In climate change taking place since then, there has been an opposite problem.  Beginning in the late 19th century, a reduction of sea ice has been progressing in the Arctic regions.  The pace of ice mass loss has been accelerating especially since the 1970s.  In the first decade of the 21st century, Greenland's ice loss accelerated at a rate of 30 gigatonnes a year.
        
             
        
        
        
Answer: Nicollo Machiavelli
Explanation: renaissance thinker. Machiavelli is not a medieval political thinker (as Dante Alighieri in his "Monarchy") anymore. His political thougths do not refer to metaphysical, divine realm. His political thought takes place in profane, secular realm.
 
        
             
        
        
        
True
The Paleolithic, Mesolithic and Neolithic eras occurred during the Stone Age. The correct option among all the options given in the question is option "C". The Stone Age is actually a large period of time and is considered to have covered around 3.4 million years. The Stone Age is thought to have ended anywhere between 6000BCE and 2000 BCE. It was the age when stones were widely used to serve different purposes of the people living during that time. The stones were sharpened and widely used as hunting tool by the people of the Stone Age.