<span>A similarity between humans and many other multicellular animals is that they are composed of organ systems. All multicellular organisms, including humans, must have organ systems to survive and function. </span>
Life would not exist. The ozone layer is keeping all the gasses from escaping into space. So, without the ozone layer, there would be no oxygen for animals or carbon dioxide for plants. The ozone layer also reflects space radiation and harmful UV rays back into space, preventing them getting into the Earth's atmosphere.
