Question

why are grassroots volunteers necessary for presidential campaigns? presidential campaigns are huge and expensive. grassroots volunteers vote at conventions. grassroots volunteers are a legal requirement.

Explanation:

Presidential campaigns operate on large scales with high costs. Volunteers provide free labor for tasks like canvassing, phone banking, and event support, reducing financial burdens and expanding reach. The other options are incorrect: grassroots volunteers do not typically have voting rights at major party conventions (delegates do), and there is no legal mandate requiring campaigns to use grassroots volunteers.

Answer:

Presidential campaigns are huge and expensive.