Moving to the next question prevents changes to this answer. Question 13
The purpose of the myelin that surrounds the axon is to:
A Repair neurons within the peripheral nervous system.
B. Help electrical currents cross the synapse completely
Oc. Keep nerve cells continually active.
D. Protect, insulate, and speed the transmission of an impulse down the axon.
A Moving to the next question prevents changes to this answer,

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.