What disease disables the bodys immune system? ?

The circles, or orbits, for electrons are called energy levels. each level can hold only a certain number of electrons. add electrons to each level until you can't add any more. how many electrons can each level hold?

If you have a difficult time knowing where your hand is without looking at it you may be having a problem with your what ?

What type of weather does tropical continental air bring in summer? hot and cloudy cool and sunny hot and sunny cool and cloudy