From your dashboard, head to your Impact Giving campaign in the Donation Campaigns section, and click Manage.
Now that you're on your campaign's Overview page, scroll until you see the All donations table.
To view the responses to your questions, simply click on the items for a donor under the IMPACT ITEMS column to view the details of their purchase.
A pop-up will appear, displaying all custom questions and the answers for the item(s) purchased in that donor's transaction.