In the past Muslim women required to wear hijab's. This is because they were told that they should not attract attention. Muslim women today have a choice to wear the hijab. Meaning that they don't have to wear it if they don't want to. Some Muslim women wear it to follow the Muslim tradition or because they want to maintain modesty and privacy from unrelated males.
Oasis is an area of grass and water in the desert. They are important because Oases provide a place to fill up on food and water supplies. They are also important to the Travelers and transportation routes in desert areas. Caravans must travel through oases so that supplies of water and food can be restocked. Travelers usually stop at an oasis when they are traveling as well.
Mosque is a place where Muslims warship there one god Allah. A Mosque will always contain a water source or fountain so they can wash their hands, arms, feet, and head for when they pray. Finally there will always be a wall in a Mosque facing Mecca so that Muslims know where to pray in the right direction.