Lewis has two spheres made of different substances. sphere a has a volume of 19.4 cubic centimeters and a mass of 24.0 grams. sphere b has a volume of 17.0 cubic centimeters and a mass of 13.6 grams. lewis knows that the density of water is 1.0 gram/cubic centimeter. if lewis places both spheres in a tub of water, which will float? a sphere a will float because it is less dense than sphere b. b sphere a will float because it has more mass than water. c sphere b will float because it has less mass than sphere a. d sphere b will float because it is less dense than water.

Female luna moths (actias luna) attract males by emitting chemical signals that spread through the air. a male hundreds of meters away can detect these molecules and fly toward their source. the sensory organs responsible for this behavior are the comblike antennae visible in the photograph shown here. each filament of an antenna is equipped with thousands of receptor cells that detect the sex attractant. based on what you learned in this chapter, propose a hypothesis to account for the ability of the male moth to detect a specific molecule in the presence of many other molecules in the air. what predictions does your hypothesis make? design an experiment to test one of these predictions.