67758
These factors included the effects of the appearance and disappearance of land bridges ( such as the one currently connecting North America and South America ) and the effects of periods of increased glaciation .
 North America, 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:
 North America, South America