ec2 logs say ImportError: No module named requests, yet it's installed

ec2 logs say ImportError: No module named requests, yet it's installed

In my ec2 instance, I run pip freeze | grep requests, which prints
requests==0.13.5. Yet when I run my server with python application.py, the
server hangs, and when I snapshot the logs, I see this error: ImportError:
No module named requests
In my ec2 instance, when I run python and call import requests, it imports
it just fine. What's preventing my flask application from seeing the
requests module?