Final answer:
Portugal explored Africa, Asia (India), and South America during the European Age of Discovery.
Step-by-step explanation:
The country that explored Africa, Asia (India), and South America is Portugal. During the European Age of Discovery, Portugal emerged as one of the leaders in exploration, establishing trading posts along the West African coast, in India, and later in the Spice Islands.
They also sailed around southern Africa, reaching Asia through this new route. Their explorations expanded their influence across these continents.