Anyone know what this Mark on my computer could be? Not sure how it got there

You are almost finished updating a web site. as part of the update, you have converted all pages from html 4.0 to html5. the project is currently on schedule. however, your project manager has been asked by the marketing team manager to justify a day of time spent validating the site's html5 pages. the marketing team manager does not have technical knowledge of the internet or the web. which is the most appropriate explanation to provide to the marketing team manager?

To check whether your writing is clear , you can

What are two ways to access the options for scaling and page orientation? click the home tab, then click alignment, or click the file tab. click the file tab, then click print, or click the page layout tab. click the page layout tab, or click the review tab. click the review tab, or click the home tab?