Why is extinction of a species most likely to occur as a environmental change

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

Select all of the statements which are true. electrons are located in shells or orbits around the atom. electrons orbit slowly around the atom. electrons travel in one flat path around the nucleus of an atom. the valence of an atom is determined by the number of electrons in the atom's outermost shell.

Which are forms of frozen water? check all that apply. dew frost hail rain sleet