user interface design (homework)

1. Define two W3C accessibility guidelines using examples.
2. Jakob Nielsen published 10 usability heuristics for user interface design. Can these heuristics be used for Web interfaces? Explain using examples.
3. A well-known user interface design guideline is stated in two different guideline sets, "Visibility of system status - Nielsen" and "Offer informative feedback - Shneiderman". What can a designer do to follow this guideline for a software application? Explain using examples.

links:

 https://www.nngroup.com/articles/ten-usability-heuristics/ 

 https://www.usabilitybok.org/heuristic-evaluation 

 https://www.w3.org/WAI/fundamentals/accessibility-intro/