The correct answer is - A. replacing natural vegetation with cultivated crops.
The natural vegetation is perfectly adapted to a certain environment, and it is also able to keep the soil tight with its roots, so the erosion is minimal.
When the natural vegetation is replaced by cultivated crops, than a problem occurs in the erosion of the soil. That is because the cultivated crops, in general, do not have root systems that are as strong and widespread as the natural vegetation, thus the soil becomes loosened up, so it is much easier to be eroded.
The biggest national park of USA is Wrangell- St. Elias National Park And Reserve
Answer: A political map shows different time zones.
Explanation: I hope this helps :) You've got this!
Answer:
The Panama canal
Explanation:
Opened in 1914, the Panama canal allows maritime traffic to travel between the Pacific and Atlantic oceans very rapidly through a system of locks (2 on the Pacific side, one in the Atlantic side), and the boats pass through an artificial lake crossing the whole country of Panama.
It takes just a few hours to cross from one side to the other, while it would take weeks to go down to the tip of South America and back up.
In 2016, the canal opened new locks, that can receive larger boats.
