Carlos trains a pigeon to peck a disk by reinforcing each disk peck. Once the response is learned, Carlos begins to cut back on the reinforcers. At first he reinforces every other response, then every third response, every fifth response, every tenth response, and so on. Carlos is using a procedure called .

Describe the location of the pyrenees: what are the 4 regions of the united kingdom: describe the danube river: describe the ural mountains: describe the location of the scandinavian peninsula: describe the european plain: describe the location of the alps: what are the effects of acid rain on germany’s black forest? what are the main causes of air pollution? how is the uk’s government is solving the air pollution problem? describe the effects of the nuclear explosion in chernobyl: describe the population distribution of russia: explain why russia’s natural resources are difficult to use: describe the slavic language family: describe the germanic language family: describe the romance language family: locate where all three religions originated: classify the three religions according to the date each began: list the holy book for each religion: exploration 1. prince henry the navigator is from which european country? 2. which 4 european countries had huge empires around the world? 3. which 4 european countries had colonies in the americas? 4. what religion did the early european explorers hope to spread? 5. where did christopher columbus land in 1492? 6. why was prince henry nicknamed “the navigator”? russian revolution 7. what type of government did czar nicholas ii have in russia? 8. what was one cause of the russian revolution? 9. what role did vladimir lenin play in the russian revolution? 10. what year did lenin bring communism to russia (soviet union)? treaty of versailles 11. what were the terms of the treaty? 12. why did france want the treaty to be harsh? world war ii 13. who was the leader of the nazi party in germany? 14. what happened to people who spoke out against hitler? 15. the holocaust occurred during which war? cold war 16. what are the dates of the cold war? 17. which two superpowers engaged in the cold war? 18. what was the purpose of the berlin wall? *locate portugal & germany on a map.