What is the thing called that holds water in a desert?

You should post answer choices if you have them. Without answer choices I would have to say that the answer is "Oasis".

There are many things that can hold water in a desert. One is oasis, which is a part of a desert that has water and plants and where people from a desert gather to rest and recuperate. One can be a waterskin which is commonly used by people who go through desert to conserve water and drink from it. A third thing can be a cactus which holds water inside of itself for long periods of time to survive. Camels hold water in their humps.