Answer:
The answer is easy and difficult, respectively.
Step-by-step explanation:
According to Chess and Thomas, there are three different types of temperaments: easy, difficult and slow to warm up.
Easy children like Evan adapt quickly to new experiences, and difficult children like Isaac present negative reactions like crying, and have problems engaging in routinary activities. Finally, the "slow to warm up" temperament is a sort of in-between: they present low levels of activity but adapt over time.