What is the reason why manga have to cover a diverse range of themes?

M: Manga is the Japanese word for comics and print cartoons. In their modern form, manga date from shortly after World War II but have a long, complex history in earlier Japanese art. In Japan, manga are widely read by children and adults of all ages, so that a broad range of subjects and topics occur in manga, including action/adventure, romance, sports and games, historical drama, comedy, science fiction and fantasy, mystery, horror, sexuality, and business and commerce, among others. Since the 1950s, manga have steadily become a major part of the Japanese publishing industry, representing a 481 billion yen market in Japan in 2006 (approximately 4.4 billion dollars). Manga have also become increasingly popular worldwide. In 2006, the United States manga market was $175～200 million.
    Manga are typically printed in black-and-white, although some full-color manga exist. In Japan, manga are usually serialized in telephone book-size manga magazines, often containing many stories each presented in a single episode to be continued in the next issue. If the series is successful, collected chapters may be republished in paperback books called tankobon. A manga artist typically works with a few assistants in a small studio and is associated with a creative editor from a commercial publishing company. If a manga series is popular enough, it may be animated after or even during its run although sometimes manga are drawn centering on previously existing live-action or animated films (e.g. Star Wars).
    Manga as a term outside of Japan refers specifically to comics originally published in Japan. However, manga and manga-influenced comics, among original works, exist in other parts of the world, and it’s style has influenced not only writers and artists, but musicians as well. Turkish rock band manga has not only its name derived from the style; their videos and album cover feature manga-style animation and the members of the band have their own manga characters, drawn by award-winning artist Kaan Demircelik.