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.
Yes, your ear canal is connected to your brain.
The body needs calcium and phosphorous because phosphorus works with calcium to help build bones
The answer is C. RNA, but it should really by called mRNA for Messenger RNA
