One of the most unusual aspects of virus particles is the absence of all organelles and other smaller structures. Whereas cells have many kinds of organelles, viruses consist of only two parts: a nucleic acid core made of DNA or RNA, and a tough, potective protein shell. Which name is given to this tough shell made of protein?

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.