Solar radiation travels through the earth's atmosphere and warms the planet's surface. greenhouse gases like carbon dioxide in the earth's atmosphere reabsorb the heat and warm the planet. the amounts of greenhouse gases have been increasing over the past century, causing the earth's surface temperature to increase. this gradual temperature change is thought to have many negative environmental consequences. which of these might be a positive effect of the increase in carbon dioxide levels? a) rise in sea levels b) decrease in plant growth c) increase in plant growth d) increased melting of ice caps

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.