Why is meiosis called reduction division?

What is the chance of two parents with blood types ab and o producing an offspring with blood type o a.0% b.25% c.75% d.50%

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?

What is the difference between the conducting zone and the respiratory zone of the respiratory system? the conducting zone is a series of cavities and tubes that move air to the respiratory zone where gases exchange with the bloodstream. the conducting zone exchanges gases between the lungs and the alveoli and the respiratory zone is a series of cavities and tubes that move air to the conducting zone. the conducting zone moves oxygen into the cells and the respiratory zone takes carbon dioxide away from the cells. the conducting zone moves oxygen into the bloodstream and the respiratory zone takes carbon dioxide away from the bloodstream.