Complex sentence: Therefore, the persona one presents to other people varies according to the social environment the person is engaged in, in particular the persona presented before others will differ from the persona an individual will present when he/she happens to be alone.
Split into simpler sentences: Therefore, the persona one presents to other people varies according to the social environment the person is engaged with. In particular, the persona presented before others will differ from the persona an individual will present when he/she happens to be alone.