what challenges do you think made it difficult for explorers to circumnavigate the world for the first time

Circumnavigation is the complete navigation around an entire island, continent, or astronomical body (e.g. a planet or moon). This article focuses on the circumnavigation of Earth.

The first recorded circumnavigation of the Earth was the Magellan-Elcano expedition, which sailed from Seville, Spain in 1519 and returned in 1522, after crossing the Atlantic, Pacific, and Indian oceans. Since the rise of commercial aviation in the late 20th century, circumnavigating Earth is straightforward, usually taking days instead of years.[1] Today, the challenge of circumnavigating Earth has shifted towards human and technological endurance, speed, and less conventional methods.

Explanation:

united states reinforcements contributed greatly to three allied victories in france at: cantigny (first major american battle), argonne (the largest in the united states military history, involving 1.2 million american soldiers), and château-thierry (one of the first actions under general pershing).

b. ensure mutual protection from communism.

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