Final answer:
The greatest ethical concern in regards to the researchers obtaining and using HeLa cells for research was using the cells for research without the patient knowing.
Step-by-step explanation:
The greatest ethical concern in regards to the researchers obtaining and using HeLa cells for research was using the cells for research without the patient knowing. Henrietta Lacks' cells were taken without her knowledge or consent, which raises serious ethical questions about informed consent and patient autonomy. This lack of consent not only violated Lacks' rights as an individual but also raised wider questions about the ethical treatment of human tissue in research.
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