Complex sentence: As social beings, humans benefit from establishing close relationships (i.e., nurturance, reproductive success, and social connection) (1) and therefore humans have a fundamental need and desire to maintain positive social ties and social inclusion (2).
Split into simpler sentences: As social beings, humans benefit from establishing close relationships (i.e., nurturance, reproductive success, and social connection) (1). Thus, humans have a fundamental need and desire to maintain positive social ties in order to maintain social inclusion (2).