33959
Movement of the continents into some configurations can cause or contribute to extinctions in several ways : by initiating or ending ice ages ; by changing ocean and wind currents and thus altering climate ; by opening seaways or land bridges which expose previously isolated species to competition for which they are poorly adapted ( for example , the extinction of most of South America 's native ungulates and all of its large metatherians after the creation of a land bridge between North and South America ) .
 South America, North, South America
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 South America, North, South America