In metric terms a square foot is a square with sides 0.3048 metres in length. One square foot is the equivalent to 0.09290304 square metres. The six floors of the White House (Washington D.C., U.S.A.) have a combined floor-space area of approximately 55,000 square feet.
A cactus (plural: cacti, cactuses, or cactus) is a member of the plant family Cactaceae within the order Caryophyllales.The word cactus derives, through Latin, from the Ancient Greek ÎºÎ¬ÎºÏÎ¿Ï, kaktos, a name originally used by Theophrastus for a spiny plant whose identity is not certain.Cacti occur in a wide range of shapes and sizes. Most cacti live in habitats subject to at least some drought.actus stems are often ribbed or fluted, which allows them to expand and contract easily for quick water absorption after rain, followed by long drought periods. Like other succulent plants, most cacti employ a special mechanism called  crassulacean acid metabolism  (CAM) as part of photosynthesis.
The prickly pear cactus is also called the paddle cactus and belongs to the Opuntia genus of cacti. They are also a distinct cactus species, due to their dual spike system, fixed spines and prickly glochids. The leaves or pads of cactus are called nopales and the fruit is called tuna or pear.ut there are some species of cactus that are useful in the field of health and medicine. In this article, learn about the medicinal uses of cactus plants as well as nutritional benefits of the same. Cactus Plants That Aid in Health and Medicine. All cactus plants aren't edible.