Question

how can peer relationships positively affect health?
by replacing family relationships
by influencing a persons food choices
by limiting a persons time for physical activity
by providing gatherings for consuming alcohol

Explanation:

Peer relationships can influence a person's food choices in a positive way. For example, peers may encourage healthy eating habits. Replacing family relationships is not a positive health - related effect. Limiting physical activity time is negative. Providing gatherings for consuming alcohol is also a negative behavior.

Answer:

by influencing a person's food choices