Exploration of Antarctica’s interior did not begin until _____.

a treaty was signed by 12 nations
airplanes were strong enough to withstand the winds and cold
sailors from European countries landed on pack ice
tractors were brought to the continents

Question

Exploration of Antarctica’s interior did not begin until _____.
 	
	a treaty was signed by 12 nations
	airplanes were strong enough to withstand the winds and cold
	sailors from European countries landed on pack ice
	tractors were brought to the continents

anonymous · Answer

A treaty was signed by twelve nations in an agreement to not use Antarctica for the use of mining, but for it to be used only for scientific research.