Select the statements about the k-t boundary that are true. select all that apply. select all that apply. the k-t boundary is a thin layer of clay found only in gubbio, italy. the k-t boundary in zumaia, spain is sharp--representing an abrupt change in the marine ecosystem. the k-t boundary separates rock layers of the cretaceous period from those of the tertiary period. the k-t boundary dates to 65 million years ago (when the dinosaurs disappeared).

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.