The correct answer for the given question above would be option A. The two organ systems that regulate homeostasis in our bodies are nervous and endocrine. The nervous system is responsible in the coordination of different systems in the body, including the voluntary and involuntary function. Whereas, the endocrine system, along with the nervous system is responsible for the regulation of different hormones that are responsible for different functions in the body.
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.
The sun with out it nothing would exist it would just be a cold solid rock floating through space.
