A network of neural cells called neurons helps the human body communicate with itself. These neurons require a very specific concentration of sodium and potassium inside and outside of their cells. In order to maintain this balance a protein, which uses energy, works to pump these ions against the concentration gradient. What is this process called? A. Passive transport
B: Facilitated diffusion
C: Active transport
D: Osmosis

Look at the images of different rocks. which rocks have a fine-grained texture? check all that apply. 1 2 3 4 5

For this question look at the hydropic diagram water that is heated by the sun evaporates. select the number that represents it.

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.