Upon Entering the Thymus, Thymocytes Are Classified as Double _____

Multiple Choice

Upon entering the thymus, thymocytes are classified as double _____ with regard to coreceptors; before exiting as single-positive, naïve T cells, they pass through a period in which they are double _____.

A) positive; negative
B) negative; positive
C) Both "positive; negative" and "negative; positive" are correct.
D) Neither "positive; negative" nor "negative; positive" are correct.
E) Coreceptor expression state does not change in the thymus.