Please help ASAP! Thank you!

Is there such a thing as a social structure that constrains individual action, or is society nothing more than a figment of our imaginations?

Dr. robbins wants to know if there are different opinions regarding the value of public school education between native americans who have at least one relative who attended indian boarding school and native americans who have no family experience with indian boarding school. dr. robbins contacts 35 native american participants in each group. he wants each group to include younger as well as older adults, and a mix of male and female participants. he asks each person to complete a survey about their attitudes toward public education. the design of this study is:

Which organelle is marked with an x?