All of the above is the correct answer. Trade opened civilizations to a world of resources, literally. Physical resources were exchanged such as minerals, plants, livestock and artisan goods. The addition of these types of things helped cultured to develop and improved length and quality of life for the populations. Language was traded, people learned to communicate across cultures which allowed for what could be considered the most valuable commodity exchanged: knowledge. People exchanged ideas, experiences, philosophies, medical practices, and so much more. They taught other cultures their agricultural skills while learning the hunting skills of a faraway land.
Civilizations and empires gained access to resources necessary to survive as well. This was received in the form of medicines such as herbs or roots that grew in different climates. Weapons and battle techniques were also shared among cultures with common interests or common enemies. These practices were vital in the growth and dominance of ancient empires because their warriors were healthier and better prepared for combat.