Final answer:
As a member of an interest group engaging in grassroots level activities, you are most likely to engage in letter writing as a form of political participation.
Step-by-step explanation:
As a member of an interest group engaging in grassroots level activities, you are most likely to engage in letter writing as a form of political participation. Letter writing allows you to communicate your concerns and opinions to elected representatives, making them aware of the issues that matter to you and your interest group. By writing letters, you can influence public policy and create change.