The right answer is Google Ads mixes and matches headlines and description lines that have been provided.
Note that responsive search ads differ from responsive display ads. Responsive search ads allow you to create an advertisement that adapts to what is searched by users. First, you enter several headlines and descriptions to offer Google Ads a few options to test. Then, over time, Google Ads tests different combinations of these headlines and descriptions and determines which of them shows the best results.
When the ad’s content is tailored to your potential customers’ search terms, leads are more likely to convert. This way, responsive search ads improve your marketing performance and can increase your profit.
To maximize the benefits of responsive search ads, carefully think about the entered headlines and descriptions. Since they will appear in any combination, headlines and descriptions must match each other. Also, the more options you enter, the more likely it is for Google Ads to find the combination that perfectly matches the search queries of your potential customers.
How does Google Ads generate responsive search ads? https://support.google.com/google-ads/answer/7684791