How many coronaviruses currently infect humans

Write a paragraph about why the respiratory system is important and we need to breathe easily. (guys i really need ) x(

Although animals share many common characteristics, there is also a great amount of diversity found in animals. which animals are ectothermic, obtain dissolved oxygen in water through gills, have scales, have fins, and live in water?

For yokos physical fitness class she is supposed to do a certain amount of aerobic exercise what is best for her