They prevented by directions and distance
the barriers were water or oceans people might say. The barriers were overcomed by ships
Oceans
the oceans
Some barriers could be that we didnt have a lot of gas and oil to use as some resoureces.
There are a few key barriers that prevent plants animals and people from reaching North America. The most prominent of these is the physical geography of the continent. The Atlantic Ocean to the east and the Pacific Ocean to the west make it quite difficult for species to traverse the continent. Additionally the Bering Strait between Asia and Alaska is a major obstacle that many species cannot pass due to its icy waters.In addition to physical geography there are also political and social actions that can prevent certain species from entering North America. For example international laws and regulations may prevent certain species from entering the continent through immigration or trade. Additionally climate change can also restrict the number of species that can reach North America by altering the temperature or precipitation in certain areas.To summarize the following are the major barriers preventing plants animals and people from reaching North America: Physical geography of the continent Political and social actions Climate changeThese barriers have a huge impact on the species that can reach and inhabit North America.
There are two natural barriers that inhibited invasion but did not totally prevent it. They are the Sahara Desert to the west & the Mediterranean Sea to the north.
bolivia
flowers
it is hard to know but almost all plants
The plant that was domesticate in North America is corn which also was domesticated in South America
north America
Transportation technology was not well-developed
All plants to a certain degree contain salt. This is because salt is everywhere in any given environment in North America.
North America