Merged Q2 (from Q2 & Q3): individuals' impacts on environmental issues

I agree with A as well. I don't think it is necessary to include "substantial" or even something along those lines. What we want to know is if the individual believes their actions have any impact on the environment so whether or not they believe it has a large impact is irrelevant for this question. If we were to have another questions asking the extent to which they feel they have an impact then it would be different.

To make it more formal though I would not use brackets. Instead use commas.

Individual efforts, including recycling, composting, biking, and using public transit, make substantial differences in environmental issues such as climate change?

(1)strongly agree (2)somewhat agree (3)neutral (4)somewhat disagree (5)strongly disagree