Q: if titan 's temperature drops below the point at which water ice sublimates into water vapor , titan 's atmospheric oxygen cycle will stop . '' '' how ? '' asked stowik as he realized that this was probably the longest conversation he had ever had with a girl . '' titan 's oxygen is replenished by the dissociation of hydrogen and oxygen when water vapor interacts with cosmic rays . reduce the water vapor , and you can say goodbye to the _ ... Fill the blank.
A: blank is oxygen

Q: never will i speak ill of a wyverian again . any wyverian . '' rhamalli folded his wing back against his side and re-hooked his wing talon to the lip of the rock outcropping he had been gripping . he nodded solemnly to the dwarf , as if rescuing falling dwarves were a daily occurrence . narrowing his eyes until they were back to being slits , rhamalli returned to his meditation , although this time he devoted a little more of his attention to keeping an eye on the _ ... Fill the blank.
A: blank is dwarves

Q: '' a curmudgeonly little bird told me today that there is a ' history ' between you and your uncle ty , '' hanson said . '' of course we have history , '' wendy said . '' he 's my uncle . '' '' i neglected to expand . i believe one might call it a violent history . '' wendy sat heavily on the bed , next to _ ... Fill the blank.
A:
blank is hanson