Bombyx mori 300 to about 900 m (1,000 to 3,000 ft) long. The fibers are very fine and lustrous, about 10 μm (0.0004 in) in diameter. About 2,000 to 3,000 cocoons are required to make a pound of silk (0.4 kg). At least 70 million pounds of raw silk are produced each year, requiring nearly 10 billion cocoons. Due to its small size and ease of culture, the silkworm has become a model organism in the study of lepidopteran and arthropod biology. Fundamental findings on pheromones, hormones, brain structures, and physiology have been made with the silkworm. One example of this was
Mori Shogunzuka Kofun Mori Shogunzuka Kofun The is a keyhole-shaped tumulus within the located in Chikuma, Nagano Prefecture Japan. The "kofun" has been restored to what modern archaeologists believe to represent its original form, with reproduction haniwa on top of the mound. Its burial chamber is closed and inaccessible to the public. There is also a museum on site, the Mori Shogunzuka Museum, which displays a reproduction of the burial chamber as well as artifacts unearthed during archaeological investigations. The cluster of four tombs has been designated a National Historic Site by the Japanese government. The Mori Shogunzuka Kofun measures approximately 100 meters