Answer:
1. Desert
2. United States
3. Explorer
Step-by-step explanation:
Given the nature of the Sahara desert, it is believed to cover about 9.4 million kilometer square. Thereby is about the same size as the United States including the region of Alaska and Hawaii.
Because of its level of hotness, it is considered very challenging to explorers.
Therefore, it can be concluded that The Sahara. The largest desert DESERT on the planet. A searing wilderness the size of the UNITED STATES The toughest challenge an EXPLORER can face.