Biology is the study of living things. Sociology is the study of human society and social problems.

A little joke i hope you will understand it : When the baby looks like his dad, then it is biology. When the baby looks like the neighbour, then it is sociology

Biology would study how your body works and keeps you alive.* Sociology would study how you work/interact with others...how you live your life (and why you live it the way you do). *Biology is the study of all living things, not just humans.