If a dog starts to put its paw down on a sharp stone, the tough skin skin protects underlying structures from damage. additionally, touch receptors in the skin send sensory signals to the spinal cord. the spinal cord then sends a signal to the muscles to lift the paw rather than continuing to press down. in this scenario, the dog may experience discomfort but avoid injury. what two body systems are being used to protect the structures beneath the dog's skin and signal the muscles to lift the paw?

the fossil record provides evidence of a common ancestor to many species.

bacteria could be both, harmful and to us. harmful bacteria could make us sick and probably even by getting the chances of getting a disease, but good bacteria fight it off with your immune system. there is always bacteria everywhere we go. we need to make sure to wash our hands after using the restroom, before eating, after eating, after petting an animal too. so you see, bacteria is everywhere and is harmful or . i hope this . : ) : ) : )

other quantities, called derived quantities, are defined in terms of the seven base quantities via a system of quantity equations. the si derived unitsfor these derived quantities are obtained from these equations and the seven si base units.