Which of the following phases has a variable volume?
solid
liquid
gas
all of the above

According to an observer on earth, planet x is stationary. maria and samir depart earth on their spaceships at the same time, each flying at 0.5c. maria flies toward planet x and samir flies in the opposite direction. according to maria, her voyage to planet x takes 9 years. how many years does maria's voyage take according to samir?

Which type of energy would have nothing to do with ironing clothes? a. heat b. chemical c. electrical d. mechanical

Which is the most accurate name for the covalent compound p2o3?