问答题 翻译：Gas and oil, either as separate fluids or in mixtures, change their state or phase as reservoir pressure changes.

问答题 翻译：Plant organisms are far more abundant than animals, and the latter are directly or indirectly when carnivorous, dependent on the former.

问答题 翻译：Viscosity μ is the measure of fluids internal resistance to flow. It has a dimension of force time Ft per unit area L.