What CSS property allows you to control the visibility of an element by changing its display?

The property that allows control over the visibility of an element by altering its display is the display property. This property determines how an element is rendered on the page. When you set the display property to values such as none, block, inline, inline-block, or flex, you are effectively controlling the element's visibility in terms of layout and presence in the DOM. For instance, using display: none will completely remove the element from the document flow, while other values will affect how the element is displayed visually and how it interacts with other elements on the page.

The visibility property, while it controls whether an element is visible or hidden, does not remove the element from the document flow as display: none would. Instead, it allows an element to occupy space even when it is not visible, making it functionally different from altering the display property.

Transparency and opacity properties are related to the visibility of an element but only in terms of visual appearance. While they can make an element more or less see-through, they do not control the element's presence in the layout like the display property does. Thus, for explicitly changing whether an element is seen or ignored by the layout algorithm of the browser, the correct answer is the display property.