The human body is the physical substance of the human organism. Characteristic of the vertebrate form, the human body has an internal skeleton with a backbone, and, as with the mammalian form, it has hair and mammary glands. Learn more about the composit
Euglena, genus of more than 1,000 species of single-celled flagellated microorganisms that feature both plant and animal characteristics. They are photosynthetic, and most species can also feed heterotrophically. Learn more about Euglena with this articl