Question: What did Ptolemy suggest that a southern land mass would do to preserve?
Sentence: However, belief in the existence of a Terra Australis—a vast continent in the far south of the globe to "balance" the northern lands of Europe, Asia and North Africa—had existed since the times of Ptolemy (1st century AD), who suggested the idea to preserve the symmetry of all known landmasses in the world.
Answer in sentence: yes