Final answer:
Mesoamericans in the Pacific Ocean and Bantu peoples in the Indian Ocean were societies engaged in intensive maritime trade on their borders in the 15th century.
Step-by-step explanation:
In the fifteenth century, the societies engaged in intensive maritime trade on their borders included:
Mesoamericans in the Pacific Ocean: Mesoamerican societies, such as the Aztecs and Maya, relied on maritime trade routes along the Pacific coast.
Bantu peoples in the Indian Ocean: Bantu-speaking communities in East Africa had flourishing maritime trade networks in the Indian Ocean, particularly along the Swahili coast.
The Chinese also engaged in intensive maritime trade in the Indian Ocean, but their presence on the borders is not specified in the given options. The Russians, on the other hand, were not known for their maritime trade activity in the Pacific Ocean during the fifteenth century.