I want to know the answer to the following question:
What did India supply to the Persian war efforts against Greece?
All the background I'm provided with is that "In 530 BC Cyrus the Great, King of the Persian Achaemenid Empire crossed the Hindu-Kush mountains to seek tribute from the tribes of Kamboja, Gandhara and the trans-India region (modern Afghanistan and Pakistan).". Is that enough to answer the question?