Billy always walks to Kindergarten. His mom always picks him up at school after Kindergarten on her way home from work. One day, mom asks Billy to walk home from Kindergarten by himself. Billy insists he does not know how to walk home from Kindergarten -- he only knows how to walk to Kindergarten. Which cognitive operation does Billy apparently lack?

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.

Ead the sixth amendment to the constitution. in all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial, by an impartial jury of the state and district wherein the crime shall have been committed . . and to be informed of the nature and cause of the accusation; to be confronted with the witnesses against him; to have [the opportunity] for obtaining witnesses in his favor, and to have the assistance of counsel for his defense. what part of the sixth amendment suggests that accused persons will be able to hear the charges against them?

Feathers wings and the hollow bones of birds are examples of