Comments are enclosed in tags. True. True. 30 seconds . Next: In the example above, we opened the p element first, then opened the strong element. When specified, the element is required. There are two important categories of elements to know in HTML: block-level elements and inline elements. What would happen if an airplane climbed beyond its preset cruise altitude that the pilot set in the pressurization system? Why do we kill some animals but not others? As mentioned earlier, that line will not get displayed in the browser. In HTML, what does the