Ever since she was a few weeks old, shelly has been an unusually contented baby who slept and ate well and adapted easily to new experiences. a developmental psychologist would probably describe shelly's temperament as being:

I believe the answer is: Easy

Easy temperament refers to the type of temperament that make babies make lower impact response to the stimulus around them.

This type of temperament make it easier for the baby's willingness to adapt in a new environment or new activities.