Earnie is developing a website and has concerns that the website will look different on a smartphone, a computer, and a tablet. What kind of testing can he do to ensure the website will look good on all devices?

Domain 6: Security Assessment and Testing Practice Questions
Questions from the following topics are included in this domain: 
Designing and validating assessments and tests
Conducting security control testing
Collecting security process data
Analyzing test output data and generating reports 
Conducting and facilitating security audits