Answer:
Tuskegee.
Explanation:
As the exercise describes, one of the most shameful violations of research ethics to date, nearly 400 African American men from Tuskegee (later called the Tuskegee syphilis experiment) were not informed that they had been diagnosed with syphilis and were not provided with available, effective treatments for this illness. The aim of this study was to observe and analyze how syphilis proceded when untreated. So, this men were told they were being treated for free.
The answer is b. Marital dissatisfaction
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An Oasis because a gravel-covered plain would hurt there feet.A salted crusted flat is dangers if one little piece of water touches the salt could ruin the whole area.A rocky plateau they would have have to climb up and down the plateau and they could get hurt.A Oasis has pure water,and enough trees to keep most or all the air pure, and almost to no dangers animals