What are the two most dominant economic activities in the arid climate of South Asia? Explain why.

I have read over all my notes, the section in the textbook dedicated to South Asia, looked at several maps indicating different factors, and Googled this question, but which two specific industries are dominant in arid South
Asia continues to elude me. I was thinking perhaps herding and trade, but I am not sure as there is no evidence to support me in what I've been given. Thank you for your help.

http://www.geographynotes.com/essay/economic-activity-of-south-asia-agriculture-mineral-and-energy-resources/400

The two most dominant economic activities in the arid climate of South Asia are agriculture and trade.

To understand why these activities are dominant in the region, let's break it down:

1. Agriculture: The arid climate of South Asia poses challenges for agricultural activities. However, certain crops and farming practices are adapted to suit the conditions. In arid regions, farmers often practice subsistence agriculture, where they cultivate crops for their own consumption or for local markets. The production of drought-resistant crops like millets, sorghum, and pulses is common in the region. Additionally, some areas have access to water sources, which allows for irrigation-based agriculture. For example, the Indus River system contributes to irrigation in Pakistan, enabling agricultural productivity in the arid plains of Punjab and Sindh.

2. Trade: Despite the aridity, South Asia has historically been a hub for trade due to its strategic location. The region has served as a crossroads for trade routes connecting different parts of Asia, Europe, and Africa. The Indian Ocean, which borders South Asia, has been a major trade route for centuries. Coastal cities like Mumbai, Karachi, and Colombo have flourishing ports that facilitate international trade. These ports handle the import and export of goods, including textiles, spices, agricultural products, and manufactured items. The trade sector not only supports local economies but also generates employment and contributes to economic growth.

When searching for information, it's essential to consider various sources such as textbooks, online articles, and maps. However, without specific evidence provided, it can be challenging to determine the dominant industries in a region. In this case, understanding the geographical, climatic, and historical factors can help us identify agriculture and trade as the two dominant economic activities in arid South Asia.

Seeing as how these folks pioneered seafaring in the Indian Ocean I would consider that an important part of their economic activities : http://www.cambridge.org/us/academic/subjects/archaeology/archaeology-asia-sub-saharan-africa-and-pacific/archaeology-seafaring-ancient-south-asia

Thank you very much!