Which of the following is the characteristic feature of xerophyte stem?

Xerophytes are the plants growing in hot and dry places. For e.g. Cactus is a plant, which grows in deserts. Thus to avoid the loss of excess water through stomata, its leaves are reduced to spine like structures and it is the stem in these plants, which is green in colour and performs the functions of photosynthesis. Also their stem is thick and waxy to prevent loss of water.