Remember that prokaryotic cells are simple and do not contain membrane-bound organelles and that eukaryotic cells are more complex and do contain membrane-bound organelles, as well as a nucleus. The endosymbiosis theory explains how eukaryotic cells may have evolved from prokaryotic cells. Symbiosis is a close relationship between two different organisms. We saw that, over time, one ancient cell became the host for other ancient cells that were capable of specific activities.
aviary, An aviary is a large enclosure for confining birds. Unlike cages, aviaries allow birds a larger living space where they can fly; hence, aviaries are also sometimes known as flight cages. Aviaries often contain plants and shrubbery to simulate a natural environment.
Gorgon: In European bestiary, a strange beast of Lybia. It is described as having high, thick eyelids with eyes that look neither upward or forward. From its crown to its nose, it has a long, hanging mane.