Animals are a major group of multicellular organisms, of the kingdom Animalia or Metazoa. Their body plan becomes fixed as they develop, usually early on in their development as embryos, although some undergo a process of metamorphosis later on in their life. Most animals are motile - they can move spontaneously and independently. Animals are heterotrophs - they are dependent on other organisms (e.g. plants) for sustenance. Most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago.------------Since the 1970s, cuteness (可愛さ, kawaisa) has become a prominent aspect of Japanese popular culture, entertainment, clothing, food, toys, personal appearance, behavior, and mannerisms. Foreign observers often find this cuteness intriguing and sometimes strange because the Japanese employ it in a vast array of situations and demographics where, in other cultures, it would be considered incongruously juvenile or frivolous (for example, in government publications, public service warnings, office environments, military advertisements, and commercial airliners, among many others).--------------------As a cultural phenomenon, cuteness is increasingly accepted in Japan as a part of Japanese culture and national identity. Tomoyuki Sugiyama, author of "Cool Japan", believes that "cuteness" is rooted in Japan's harmony-loving culture, and Nobuyoshi Kurita, a sociology professor at Musashi University in Tokyo, has stated that "cute" is a "magic term" that encompasses everything that's acceptable and desirable in Japan.