A good piece of evidence is typically specific, relevant, and supports a claim or argument effectively. An example could be:
"A study published in the Journal of Environmental Science found that cities that implemented green roofs reduced urban heat by an average of 5 degrees Fahrenheit during summer months, demonstrating the effectiveness of sustainable architecture in mitigating climate change."
This statement provides specific data from a credible source and directly supports a claim about the benefits of green roofs in urban settings.