Prokaryotes do not have membrane bound organelles, but eukaryotes do.
The rough ER is involved with protein synthesis. It helps to produce proteins and help them fold properly.
I think the hydra lacks the specialized cells for touch and chemical detection. On the other hand earthworms have touch, light, vibration and chemical receptors along the entire body surface. Both of them are invertebrates (those animals without a backbone), they include insects, worms, jelly fish, spiders among other animals.
Answer: Mesopotamia, china, indus River Valley, the mesoamerican empires..... in this case, the two rivers are the tigris and Euphrates. Mesopotamia. The name Mesopotamia was given to the middle eastern civilizations that existed between the Euphrates and Tigris Rivers. :)
