yes
Just the basic information about your parent's identity, like their name, date of birth, and social security number; their living situation, marital status, state of residence, household size, and financial circumstances.
How should I respond if they are separated?
That would depend on if your parents live together or not. If your parents are married but are considered legally separated by a state, or if they legally married but have chosen to live separate lives then they are considered separate, as if they weren't married.