Ron has not used heroin for several days. He has a headache, is hallucinating, having flashbacks and
vomiting. Which of the following best describes the
phenomenon that he is experiencing?
O tolerance
o withdrawal
O behavioral dependence
O all of the above

Hydroelectricity provides about 7 percent of the electricity generated in the united states. (a) explain how a hydroelectric power plant converts energy stored in water into electricity. (b) identify two factors that determine the amount of electricity that can be generated by an individual hydroelectricity power plant. (c) describe the two main types of land-based hydroelectric power plants. (d) describe two economic advantages and two environmental disadvantages of hydroelectricity.