1. He studies animals in South America.

Question

2. He studies the animals in South America.
..............
Q1: What is the difference in meaning between them?
Q2: Is 'in South America' an adverb phrase or an adjecive phrase? Or are both okay in meaning?

Does the sentence above mean the following? <one of them?>
a. He is now in South America and studies animals there.
b. He is not in South America, but he studies animals there.
c. He maybe in South America, or he may not be in South America. Anyway he studies animals there.