What are two reasons scientists might use a model to study what happens on the atomic level when something explodes?
A. The process is very dangerous to study.
B. The molecules in the reaction are too small to see.
C. The process cannot be understood without a model.
D. Explosions occur too slowly to study easily.

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.

The first generation of offspring from the cross of two parents is called the a. f1 generation b. f2 generation c. short generation d. p generation

Ivan is looking at a cross section of a stem taken from a vascular plant. he sees two different types of vascular tissue: the xylem, which is closer to the center of the stem, and the phloem, located around the xylem, closer to the outside of the stem. how do these two structures work together in a living plant?