Antarctica is correctly identified as the continent with the highest mean elevation in the world. The reason being the presence of an extensive ice sheet that covers the entire landmass. Even though Mount Everest in Asia is the highest peak above sea level, the overall or mean elevation of the Asian continent is significantly lower as it includes vast areas of lowlands.

The North American continent, while it also has high peaks such as Denali in Alaska, also includes substantial expanses of flat or low-elevation areas, which brings down the mean elevation of the continent.

In the case of South America, while it houses the Andes (the world`s longest continental mountain range), it also includes the Amazon basin which is quite flat, hence the overall elevation is substantially lower than that of Antarctica.

Thus, in terms of mean elevation (which is not about the highest peak but rather about the average elevation across the entire continent), Antarctica is indeed the highest in the world. It stands an average of about 2,200 meters above sea level.