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

Answer 1

The answer is "airplanes were strong enough to withstand the winds and cold ".

Step-by-step explanation:

Answer 2

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.