(i) (a) an endless stretch of sand where no rainfalls.
(b) dry, hot, waterless and without shelter.
(ii) (a) a beautiful place.
(b) home of a variety of people, animals and plants.
Description by specialists is more apt which is based on their studies.
(i) an endless stretch of sand. --- nothing but sand as far as one can see
(ii) waterless and without. --- no water and no shade
(iii) an oasis. --- fertile place with water and plants in desert
(iv) hidden by a cover of grass --- not visible because the grass shelter is thick
A camel can do survive without water for many days together because they sweat very less. Camels have high body temperature so they don't need to sweat and therefore, can retain the water they drink for long period of time.
The small desert animals fulfill their requirement for water by burrowing underground during the hot days and come out at night for feeding. Some of them eat other animal and the water they need from the moisture in the meat, other eat seeds and plants and get the water that they need from plant juices.
In desert lands, moisture is absent during the day. The moisture present in the air acts as blanket that protects the earth's surface from the harmful UV rays of the sun but the moisture in the air is absent in desert. Therefore, the moisture land gets heat up very rapidly during the day due to the sun's rays and cools down rapidly at night.