What are the causes of a low blood oxygen level?

What disease is nick suffering from nick observes thickening and discoloration of the nail of the index finger nick is most likely suffering from a what infection

So i have a lot of answers answered but it says i still need to answer more questions. why is it doing that? how many questions need to be answered?

Match the limiting factor with the correct definition. 1. learning about the benefits of exercise location/access 2. problem that can be solved by choosing free activities understanding 3. living close to a park motivation 4. how you were raised money 5. how you feel about yourself and your ability to exercise family behaviors