> People has different eyes. I think people lived in different places and environment for a long time.

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* Correction:     Student's sentence        Corrected sentence        Grammar explanation       Better sentence    

1. People has different eyes.

People have different eyes.

"People" is a plural noun, so you should use "have"

People have different eye colors.

2. I think people lived in different places and environment for a long time.

I think people have been living in different places and environment for a long time.

"Lived" is simple past which means the action is finished, but I think what you mean is from the past until now, so that is present perfect continuous. therefore, you should use "have + been + (ing)verb"

I think people have different eye colors because they have been living in different places and environment for a long time.