Infant rats deprived of their mothers' normal licking had more ________ that block access to the "on" switch for developing the brain's stress hormone receptors.

Question

Quizplus · Accepted Answer

The question mentions that the infant rats were deprived of normal licking by their mothers, which suggests that this was a behavioral manipulation rather than a genetic or cellular one. The missing form of maternal care likely influenced the rats' epigenetic environment, which refers to modifications to gene expression that do not involve changes to the DNA sequence itself. The question further specifies that these changes blocked access to stress hormone receptors in the developing brain, which is consistent with the idea that epigenetic changes may alter the expression or function of specific genes. Therefore, the best choice is D, epigenetic molecules. The other options may have secondary effects on gene expression or brain development, but they are less directly tied to the specific findings described in the question.

Infant Rats Deprived of Their Mothers' Normal Licking Had More