Answer:

1.cactus (plural: cacti, cactuses, or less commonly, cactus)[3] is a member of the plant family Cactaceae,[Note 1] a family comprising about 127 genera with some 1750 known species of the order Caryophyllales.[4] The word "cactus" derives, through Latin, from the Ancient Greek κάκτος, kaktos, a name originally used by Theophrastus for a spiny plant whose identity is not certain.[5] Cacti occur in a wide range of shapes and sizes. Most cacti live in habitats subject to at least some drought.

2.Polar bears have white fur so that they can camouflage into their environment. Their coat is so well camouflaged in Arctic environments that it can sometimes pass as a snow drift. Interestingly, the polar bear’s coat has no white pigment; in fact, a polar bear’s skin is black and its hairs are hollow. They have a thick layer of body fat, which keeps them warm while swimming, and a double-layered coat that insulates them from the cold Arctic air.