Hey i need with this! i know it's no b, so can you guys me find the answer?
which phrase describes an oasis?
a. an area of a rain forest where tall trees grow
b. an area of a desert that is dry and sandy
c. an area of a rain forest that has standing water
d. an area of a desert that has water and vegetation

1u.s. history question! question: how did world war ii change the united states' position in world affairs? i need good explanation to support the answer otherwise i get docked points. real answers only ! you! : )

Idont know any of these can anyone me

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.