can someone tell me how flatworms remove waste??? Is it through their tubule? What's a tubule.. im so confused

Faltworms rely on difussion to transport oxygen and nutrients to their internal tissue and to get rid of carbon dioxide and other wastes from their body . Flateworms have no heart ,blood, blood vessels, grills , or other respiratory systems. Flatworms have flame cells. Flame cells are specialized cells that remove and purify excess water from the body.

imagine a line passing through the center of earth that goes through both the north pole and the south pole. this imaginary line is called an axis. earth spins around its axis, just as a top spins around its spindle. this spinning movement is called earth's rotation. at the same time that the earth spins on its axis, it also orbits, or revolves around the sun. this movement is called revolution.

what are the awnser choices? i mean, without choices, it is an incompleat