Final answer:
Young adults and students were the group most likely to support the environmental movement from the 1960s to the 1980s, catalyzed by concerns over pollution, deforestation, and global warming.
Step-by-step explanation:
The groups most likely to support the growing environmental movement in the 1960s through the 1980s were young adults and students. During this period, environmentalism evolved from earlier conservation efforts, reacting to the rapid industrialization and the emergence of issues such as pollution, deforestation, and global warming. Activism from young adults and students gained momentum after observing the negative impacts of economic growth and industrialization on the natural environment.
These concerns were catalyzed by events such as the publication of Rachel Carson's 'Silent Spring' and the establishment of Earth Day in 1970, often driven by the academic community and other grassroots organizations. This group voiced their concerns about a variety of environmental issues and worked to promote change through measures like the Clean Air Act of 1963 and by setting aside April 22, 1970, as a day of learning and discussion of environmental issues, now known as Earth Day.