A scientist wants to use a model to help present the results of his detailed scientific investigation. Why would a model be useful?

Which is the layer underground where all empty spaces are filled with a combination of air and water ?

Modern weaponry has increased the number of deaths in wars and violent conflicts.

Astable electron arrangement for an atom is one that does not easily change. how is this arrangement arrived at? a. valence electrons are transferred or shared to create a full outer shell of electrons. b. valence electrons are discarded into space to create a full outer shell of electrons. c. protons (positive charge) pair with valence electrons (negative charge) to create a strong bond. d. outer shells with valence electrons are transferred or shared.