What is grassroots lobbying, and how does it differ from direct lobbying?

What will be an ideal response?

Grassroots lobbying involves organizations mobilizing citizens to pressure their senators and representatives. Instead of meeting with members personally, as in direct lobbying, they instead use various tools (such as phone calls or social media) to generate communication to members’ offices from their districts. This type of lobbying may be particularly effective because members know they must keep their constituents happy to remain in office.