In the tuskegee syphilis experiments, what information did researchers keep from their subjects about their illnesses? a. they were told they had a rare form of syphilis. b. they were not treated for or told they had cancer. c. they were told they had a sexually transmitted infection. d. they were not treated for or told they had syphilis.

The correct answer is option D. "They were not treated for or told they had syphilis".

Explanation:

The infamous Tuskegee syphilis experiments, known as the “Tuskegee Study of Untreated Syphilis in the Negro Male”, involved experiments in 600 African  Americans (399 with syphilis and 201 healthy patients). In these experiments the researchers did not tell the subjects if they were not treated for or told they had syphilis. The study was labeled as “ethically unjustified” and was stopped in October 1972.

d.

Explanation:

answer; the tunica intima also called tunica interna, consists of elastic fibers,connective tissue and smooth muscle cells;