This chinese invention allowed ships to move their sails and to sail into the wind for the first time.

Sam and ben have discovered some strange animals living in the woods behind their house. ben is excited because he believes they are marsupials, an animal he's never observed in the wild before. his brother is sure it is not. what feature should the boys consider in deciding whether the animals are marsupials?

A“carpetbagger” would have been most likely to come from which state?

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.