3. What groups/individuals were at the root of the
movement to push for reforms?

The correct answer to this open question is the following.

Although there are no options attached, context, or further references, we can comment on the following.

Among groups/individuals who were at the root of the movement to push for reforms were the American workers, the members of the Suffrage Movement, and Muckracker Journalists,

We are talking about the Progressive Era in the United States after the period called the Gilded Age, which was characterized by corruption acts in US politics and the growth of monopolies.

The groups that were involved in this Progressive Era demanded changes after the consequences of industrialization, immigration, overpopulation, and corruption in the government.

answer; (a) he was a u.s senator for 38 years;

c.) biotic: snails; abiotic: temperature climate