Answer:
Individual differences
Explanation
In psychology, no two people are the same there will be some aspects of difference due to the principle of dissimilarity in nature.
The differences or variation can be the way they think, two individuals can not think exactly the same way.
It can be how they show emotions such as love, hate or pain. Also their personality and behavior.
These variations are influenced by many factors such as enviroment, gender, race or age of the individuals.