Denise wants to find out how the steepness of a hill's slope affects the amount of soil that erodes from it. she will use soil, a long pan, and several 4-inch-tall wooden blocks to build a model hillside. she will use a watering can to simulate rainfall. in her experiment, which factor should be denise's variable? a. the amount of water she pours on the model hillside b. the type of soil with which she fills the pan c. the number of blocks holding up the end of the pan d. the location she uses to test her model

Cells are adapted to preform specific functions. which of the following terms refers to this capability?

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.

Which line in the graph above best illustrates an effect of the carbon dioxide level in the blood on breathing rate before, during and after a period of exercise? 1.b,2.c,3.a,4.d