Final answer:
Argentina and Chile are the two South American countries that lay claim to part of Antarctica.
Step-by-step explanation:
The two South American countries that lay claim to part of Antarctica are Argentina and Chile.
According to the Antarctic Treaty System, which was signed in 1959, no new territorial claims can be made on the continent. However, Argentina and Chile are two of the original claimant countries that were allocated a portion of Antarctica based on their historical claims. Other countries have reserved their right to submit claims in the future if the issue of territorial claims becomes significant.