Surveys are listed based on availability or on an offer that matches your profile. They get updated frequently; so keep coming back to check if there's one available for you.
Note that using a VPN or Proxy Services could limit your access to surveys.

Surveys are provided by a third-party, TapResearch;  they are currently supported in the following countries:
  • USA, Canada, Great Britain, Australia
  • France, Germany, Italy, Spain, Norway, Denmark, Finland, Sweden
  • Brazil, Mexico
  • Hong Kong, Singapore, South Korea, India, China
You can check their FAQs here.