Which of the primary features of grassroots progressivism was the most essential to the continued growth and success if the reformist movement?  

1. It helps to raise money

2. Deepens political participation

3. It help to raise awareness massively.

Explanation:

grassroots movements aim to raise money, build organizations, raise awareness, build name recognition, to win campaigns, and to deepen political participation.

In the modern era, a movement that identifies as progressive is "a social or political movement that aims to represent the interests of ordinary people through political change and the support of government actions In the 21st century, those who identify as progressive may do so for a variety of reasons: for example, to favor public policy that reduces or ameliorates the harmful effects of economic inequality as well as systemic discrimination, to advocate for environmentally conscious policies, as well as for social safety nets and rights of workers, to oppose the negative externalities inflicted on the environment and society by monopolies or corporate influence on the democratic process.

letter d is correct.

i know social security wasn't one.

explanation:

hope my answer has you!