Answer:
Highly productive aquifers and oasis
Explanation:
From this map, we can see that Yemen actually is a country that has a relatively high amount of freshwater reserves, despite the country having not a single river. in the coastal areas of Yemen, we can see that there's an abundance of water below the surface, stored in highly productive aquifers. Also, there's four oasis, two of which are located in the southeastern part of the country, and two others that are located in the central part, and those are very important as they are the only reserves of freshwater in that part of Yemen.
