To prevent the possibility that a placebo effect or researchers' expectations will influence a study's results, scientists employ: control groups control groups experimental groups experimental groups random assignment random assignment the double-blind procedure

Which of the following statements best describes the roles of england and france in new world? a. englandand france became involved in the americans only after a papal decision granting the control of north america. b. jacques cartier claimed canada for england in 1534. c. most of england’s voyages of exploration were focused on south america. d. english and french explorations in the arctic turned europe on to the opportunities of whaling and fishing in the area.

U. s. foreign aid incudes all the following programs excepta. humanitarian aidb. military assistancec. cycle of dependency grantsd. development aid

Which of the following was a key accomplishment of the people of songhai? a. they had a strong military and became the largest empire in west africa. b. they established a center of islamic scholarship. c. they worked with iron and prospered from the gold-salt trade. d. they dominated in the trade of ivory, enslaved people, and animal skins.