Well all animals are known for their characteristics so are placed in specific groups that match with their characteristics. Hope this helped :)
I think because they have a DNA
The nutrients get to the cells in a flatworms solid acoelomate body by diffusion process. Flatworms feed primarily on protozoa and bacteria, smaller worms and tiny organisms, dead or alive, that they come across. Based on the species of the flatworms , they also consume plant materials. They rely on diffusion to transport oxygen and nutrients to their internal tissues.
Very... Reproduction at both the molecular level to help maintain and repair itself through production of cells is important for self-preservation. Additionally reproduction allows survival of genetic material to offspring.
