You most likely have been taught this, but it may have been quite early in the year as it's unit 3 stuff.
So when they're talking about determinants they're talking about:
Biological determinants:
Factors relating to the body that impact on health such as genetics, hormones, birth weight, body weight, blood pressure and cholesterol levels.
Behavioural determinants:
Actions or patterns of living of an individual or group that impact on health such as physical activity, sexual activity, smoking and eating practices.
Social determinants:
Aspects of society and the social environment that impact on health, such as poverty, early life experiences, social networks and support.
So for example if a question asks about the variation in health status of males and females, you can talk about biological, behavioural or social determinants that either act as risk factors or protective factors.
Putting this into perspective you could say that a protective biological factor of genetics could be that the production of oestrogen in women's fertile years can be a protective factor against cardiovascular disease which can decrease premature death (YLL's) among females and may explain why females tend to live approximately 5 years longer than males.
Determinants are mainly used to explain or compare differences in health status among Indigenous and non-Indigenous Australians, people who live in rural/remote areas and people who live in urban areas, males and females, and people in high socioeconomic groups and low socioeconomic groups.
Hope this helps!