A wave traveling at 230 m/sec has a wavelength of 2.1 meters. What is the frequency of this wave?

Why did other of the delian league resent athenian control

Of the following choices, which ones are characteristics of west african society? select all that apply. a. arabic was the main language used when trading with other societies. b. christianity was the only religion practiced in villages. c. slaves had no rights and were only given specific farming tasks. d. skilled workers were a higher level in the caste system than traders. e. religious rituals encouraged the honoring of ancestors.

The authors of the paper "fudging the numbers: distributing chocolate influences student evaluations of an undergraduate course"† carried out a study to see if events unrelated to an undergraduate course could affect student evaluations. students enrolled in statistics courses taught by the same instructor participated in the study. all students attended the same lectures and one of six discussion sections that met once a week. at the end of the course, the researchers chose three of the discussion sections to be the "chocolate group." students in these three sections were offered chocolate prior to having them fill out course evaluations. students in the other three sections were not offered chocolate. the researchers concluded that "overall, students offered chocolate gave more positive evaluations than students not offered chocolate." indicate whether the study is an observational study or an experiment. give a brief explanation for your choice.