The intertidal zone is a narrow band where the ocean meets land. Organisms that live in this zone must adapt to changes that occur in daily tides and waves. In which region of the intertidal zone would the most abundant aquatic organisms be found? A. low-tide zone because it is covered with water all-day
B. spray zone because it receives some water at high tide
C. high-tide zone because it is underwater during high tides
D. mid-tide zone because it is covered and uncovered twice a day

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.