1. How is the law of conservation of mass shown by a balanced chemical equation? A) The subscripts must be the same on both sides of the equation.
B) The total volumes of the substances must be the same on both sides of the equation.
C) The coefficients must be the same on both sides of the equation.
D) The number of each type of atom must be the same on both sides of the equation.

Embryos of different species look very similar, which shows that the organisms share a ancestor.

Hot air balloons float in the air because of the difference in density between cold and hot air. in this problem, you will estimate the minimum temperature the gas inside the balloon needs to be, for it to take off. to do this, use the following variables and make these assumptions: the combined weight of the pilot basket together with that of the balloon fabric and other equipment is w. the volume of the hot air inside the balloon when it is inflated is v. the absolute temperature of the hot air at the bottom of the balloon is th (where th> tc). the absolute temperature of the cold air outside the balloon is tc and its density is ďc. the balloon is open at the bottom, so that the pressure inside and outside the balloon is the same. as always, treat air as an ideal gas. use g for the magnitude of the acceleration due to gravity.

Check the correct box to describe the periodic trends in electronegativity. electronegativity across a period: decreases. increases. electronegativity down a group: decreases. increases.