Zach, 20 months, recently started using first-person pronouns. his mother is somewhat concerned that zach constantly asserts his rights to objects, shouting, "mine! " even when playing with his brother, zach doesn’t want to share toys, instead insisting that everything is "mine." what does zach’s behavior show about his emotional development?

Sense of self-awareness

Explanation: Sense of self awareness is the characteristic through an individual becomes capable to acknowledge their-self as an separate entity from other and surroundings .The individual tends to concentrate on their own behavior, thoughts, action etc and evaluate it.

Zach is also invoked with the self awareness characteristic as he is focusing that he owns most objects like toys and remark it as its own and does not belong to other.This behavior shown that he is aware about the his belongings and rights towards objects that he own.