What pressure will be needed to reduce the volume of 77.4 L of helium at 98.0
kPa to a volume of 60.0 L?*

c

Explanation:

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.